diff --git a/miniapp/pages/index/index.js b/miniapp/pages/index/index.js
index fc30e3a..8289ea6 100644
--- a/miniapp/pages/index/index.js
+++ b/miniapp/pages/index/index.js
@@ -322,37 +322,48 @@ function applyDirection(links, direction) {
 /**
  * 根据标签位置模式返回 Canvas 文本绘制参数。
  */
-function getCanvasLabelPlacement(layout, isSource, labelPositionMode) {
-  const sourceInnerX = layout.leftX + layout.nodeWidth + 4;
-  const sourceOuterX = Math.max(2, layout.leftX - 4);
-  const targetInnerX = Math.max(2, layout.rightX - 4);
-  const targetOuterX = layout.rightX + layout.nodeWidth + 4;
+function getCanvasLabelPlacement(nodeX, nodeWidth, isSource, isTarget, labelPositionMode) {
+  const leftOuterX = Math.max(2, nodeX - 4);
+  const rightOuterX = nodeX + nodeWidth + 4;
+
+  if (!isSource && !isTarget) {
+    if (labelPositionMode === 'left') {
+      return { x: leftOuterX, textAlign: 'right' };
+    }
+    return { x: rightOuterX, textAlign: 'left' };
+  }
 
   if (labelPositionMode === 'outer') {
     return isSource
-      ? { x: sourceOuterX, textAlign: 'right' }
-      : { x: targetOuterX, textAlign: 'left' };
+      ? { x: leftOuterX, textAlign: 'right' }
+      : { x: rightOuterX, textAlign: 'left' };
   }
   if (labelPositionMode === 'left') {
     return isSource
-      ? { x: sourceOuterX, textAlign: 'right' }
-      : { x: targetInnerX, textAlign: 'right' };
+      ? { x: leftOuterX, textAlign: 'right' }
+      : { x: leftOuterX, textAlign: 'right' };
   }
   if (labelPositionMode === 'right') {
     return isSource
-      ? { x: sourceInnerX, textAlign: 'left' }
-      : { x: targetOuterX, textAlign: 'left' };
+      ? { x: rightOuterX, textAlign: 'left' }
+      : { x: rightOuterX, textAlign: 'left' };
   }
   return isSource
-    ? { x: sourceInnerX, textAlign: 'left' }
-    : { x: targetInnerX, textAlign: 'right' };
+    ? { x: rightOuterX, textAlign: 'left' }
+    : { x: leftOuterX, textAlign: 'right' };
 }
 
 /**
  * 根据标签位置模式返回 SVG 文本锚点参数。
  */
-function getSvgLabelPlacement(layout, isSource, labelPositionMode) {
-  const canvasPlacement = getCanvasLabelPlacement(layout, isSource, labelPositionMode);
+function getSvgLabelPlacement(nodeX, nodeWidth, isSource, isTarget, labelPositionMode) {
+  const canvasPlacement = getCanvasLabelPlacement(
+    nodeX,
+    nodeWidth,
+    isSource,
+    isTarget,
+    labelPositionMode
+  );
   return {
     x: canvasPlacement.x,
     textAnchor: canvasPlacement.textAlign === 'right' ? 'end' : 'start'
@@ -383,16 +394,29 @@ function buildSankeyLayout(links, width, height, renderOptions) {
   const padding = Math.min(rawPadding, Math.max(0, height / 2 - 4));
   const targetAlignMode = (renderOptions && renderOptions.targetAlignMode) || 'between';
   const nodeWidth = 10;
-  const leftX = padding;
-  const rightX = Math.max(padding + nodeWidth + 80, width - padding - nodeWidth);
+  const validLinks = links
+    .map((link) => ({
+      source: String(link.source || ''),
+      target: String(link.target || ''),
+      value: Number(link.value || 0)
+    }))
+    .filter((link) => link.source && link.target && Number.isFinite(link.value) && link.value > 0);
+  if (validLinks.length === 0) {
+    return null;
+  }
 
-  const sourceValueMap = {};
-  const targetValueMap = {};
   const nodeColorIndexMap = {};
+  const nodeOrderMap = {};
   let nodeColorIndexCursor = 0;
-  links.forEach((link) => {
-    sourceValueMap[link.source] = (sourceValueMap[link.source] || 0) + Number(link.value || 0);
-    targetValueMap[link.target] = (targetValueMap[link.target] || 0) + Number(link.value || 0);
+  let nodeOrderCursor = 0;
+  const incomingCountMap = {};
+  const outgoingCountMap = {};
+  const inValueMap = {};
+  const outValueMap = {};
+  const adjacencyMap = {};
+  const indegreeMap = {};
+
+  validLinks.forEach((link) => {
     if (!Object.prototype.hasOwnProperty.call(nodeColorIndexMap, link.source)) {
       nodeColorIndexMap[link.source] = nodeColorIndexCursor;
       nodeColorIndexCursor += 1;
@@ -401,107 +425,226 @@ function buildSankeyLayout(links, width, height, renderOptions) {
       nodeColorIndexMap[link.target] = nodeColorIndexCursor;
       nodeColorIndexCursor += 1;
     }
+    if (!Object.prototype.hasOwnProperty.call(nodeOrderMap, link.source)) {
+      nodeOrderMap[link.source] = nodeOrderCursor;
+      nodeOrderCursor += 1;
+    }
+    if (!Object.prototype.hasOwnProperty.call(nodeOrderMap, link.target)) {
+      nodeOrderMap[link.target] = nodeOrderCursor;
+      nodeOrderCursor += 1;
+    }
+
+    outgoingCountMap[link.source] = (outgoingCountMap[link.source] || 0) + 1;
+    incomingCountMap[link.target] = (incomingCountMap[link.target] || 0) + 1;
+    outValueMap[link.source] = (outValueMap[link.source] || 0) + link.value;
+    inValueMap[link.target] = (inValueMap[link.target] || 0) + link.value;
+
+    if (!adjacencyMap[link.source]) {
+      adjacencyMap[link.source] = [];
+    }
+    adjacencyMap[link.source].push(link.target);
+    indegreeMap[link.target] = (indegreeMap[link.target] || 0) + 1;
+    if (!Object.prototype.hasOwnProperty.call(indegreeMap, link.source)) {
+      indegreeMap[link.source] = indegreeMap[link.source] || 0;
+    }
   });
 
-  const sourceNames = Object.keys(sourceValueMap);
-  const targetNames = Object.keys(targetValueMap);
-  const totalValue = sourceNames.reduce((sum, name) => sum + sourceValueMap[name], 0);
-  if (totalValue <= 0) {
+  const nodeNames = Object.keys(nodeOrderMap).sort((a, b) => nodeOrderMap[a] - nodeOrderMap[b]);
+  const nodeCount = nodeNames.length;
+  const depthMap = {};
+  nodeNames.forEach((name) => {
+    depthMap[name] = 0;
+  });
+
+  const indegreeWorkMap = {};
+  nodeNames.forEach((name) => {
+    indegreeWorkMap[name] = indegreeMap[name] || 0;
+  });
+
+  const queue = nodeNames.filter((name) => indegreeWorkMap[name] === 0);
+  const visitedMap = {};
+  while (queue.length > 0) {
+    const current = queue.shift();
+    visitedMap[current] = true;
+    const nextTargets = adjacencyMap[current] || [];
+    nextTargets.forEach((next) => {
+      const nextDepth = Math.min(nodeCount - 1, (depthMap[current] || 0) + 1);
+      if (nextDepth > (depthMap[next] || 0)) {
+        depthMap[next] = nextDepth;
+      }
+      indegreeWorkMap[next] = (indegreeWorkMap[next] || 0) - 1;
+      if (indegreeWorkMap[next] === 0) {
+        queue.push(next);
+      }
+    });
+  }
+
+  // 图中存在环时，继续做有限轮次松弛，尽量拉开层级。
+  if (Object.keys(visitedMap).length < nodeCount) {
+    for (let round = 0; round < nodeCount; round += 1) {
+      let changed = false;
+      validLinks.forEach((link) => {
+        const relaxedDepth = Math.min(nodeCount - 1, (depthMap[link.source] || 0) + 1);
+        if (relaxedDepth > (depthMap[link.target] || 0)) {
+          depthMap[link.target] = relaxedDepth;
+          changed = true;
+        }
+      });
+      if (!changed) {
+        break;
+      }
+    }
+  }
+
+  const maxDepth = nodeNames.reduce((max, name) => Math.max(max, depthMap[name] || 0), 0);
+  const columns = Array.from({ length: maxDepth + 1 }, () => []);
+  nodeNames.forEach((name) => {
+    const depth = depthMap[name] || 0;
+    columns[depth].push(name);
+  });
+  columns.forEach((names) => {
+    names.sort((a, b) => nodeOrderMap[a] - nodeOrderMap[b]);
+  });
+
+  const nodeValueMap = {};
+  nodeNames.forEach((name) => {
+    nodeValueMap[name] = Math.max(outValueMap[name] || 0, inValueMap[name] || 0);
+  });
+
+  const availableHeight = Math.max(0, height - padding * 2);
+  const maxColumnNodeCount = columns.reduce((max, names) => Math.max(max, names.length), 0);
+  const effectiveGap =
+    maxColumnNodeCount > 1 ? Math.min(nodeGap, availableHeight / (maxColumnNodeCount - 1)) : nodeGap;
+
+  let unitHeight = Infinity;
+  columns.forEach((names) => {
+    if (names.length === 0) {
+      return;
+    }
+    const totalValue = names.reduce((sum, name) => sum + (nodeValueMap[name] || 0), 0);
+    if (totalValue <= 0) {
+      return;
+    }
+    const gapCount = Math.max(0, names.length - 1);
+    const candidate = (availableHeight - gapCount * effectiveGap) / totalValue;
+    if (Number.isFinite(candidate) && candidate >= 0) {
+      unitHeight = Math.min(unitHeight, candidate);
+    }
+  });
+
+  if (!Number.isFinite(unitHeight) || unitHeight <= 0) {
     return null;
   }
 
-  const sourceGapCount = Math.max(0, sourceNames.length - 1);
-  const sourceContentHeight = Math.max(0, height - padding * 2 - sourceGapCount * nodeGap);
-  const sourceUnitHeight = sourceContentHeight / totalValue;
-  const sourceTotalNodeHeight = totalValue * sourceUnitHeight;
-  const sourceSpanHeight = sourceTotalNodeHeight + sourceGapCount * nodeGap;
-
-  const sourcePos = {};
-  let sourceCursorY = padding;
-  sourceNames.forEach((name) => {
-    const nodeHeight = sourceValueMap[name] * sourceUnitHeight;
-    sourcePos[name] = { y: sourceCursorY, h: nodeHeight };
-    sourceCursorY += nodeHeight + nodeGap;
+  const columnNodeHeightMap = {};
+  const columnGapMap = {};
+  const columnBlockHeightMap = {};
+  columns.forEach((names, depth) => {
+    const totalNodeHeight = names.reduce((sum, name) => sum + (nodeValueMap[name] || 0) * unitHeight, 0);
+    let columnGap = effectiveGap;
+    if (depth === maxDepth && targetAlignMode === 'between' && names.length > 1) {
+      const sourceNames = columns[0] || [];
+      const sourceTotalNodeHeight = sourceNames.reduce(
+        (sum, name) => sum + (nodeValueMap[name] || 0) * unitHeight,
+        0
+      );
+      const sourceSpanHeight =
+        sourceTotalNodeHeight + Math.max(0, sourceNames.length - 1) * effectiveGap;
+      columnGap = (sourceSpanHeight - totalNodeHeight) / (names.length - 1);
+    }
+    columnGap = Math.max(0, columnGap);
+    const blockHeight = totalNodeHeight + Math.max(0, names.length - 1) * columnGap;
+    columnNodeHeightMap[depth] = totalNodeHeight;
+    columnGapMap[depth] = columnGap;
+    columnBlockHeightMap[depth] = blockHeight;
   });
 
-  const targetGapCount = Math.max(0, targetNames.length - 1);
-  const targetTotalValue = targetNames.reduce((sum, name) => sum + targetValueMap[name], 0);
-  const targetUnitHeight = targetTotalValue > 0 ? sourceUnitHeight : 0;
-  const targetTotalNodeHeight = targetTotalValue * targetUnitHeight;
-  let targetGap = nodeGap;
-  if (targetAlignMode === 'between' && targetNames.length > 1) {
-    // 与 Web 端一致：两端对齐时，目标列整体高度与 source 列跨度一致。
-    targetGap = (sourceSpanHeight - targetTotalNodeHeight) / (targetNames.length - 1);
-  }
-  targetGap = Math.max(0, targetGap);
+  const sourceSpanHeight = columnBlockHeightMap[0] || 0;
+  const leftX = padding;
+  const rightX = Math.max(padding + nodeWidth + 80, width - padding - nodeWidth);
+  const columnStep = maxDepth > 0 ? (rightX - leftX) / maxDepth : 0;
 
-  const targetBlockHeight = targetTotalNodeHeight + targetGapCount * targetGap;
-  let targetStartY = padding;
-  if (targetAlignMode === 'middle') {
-    targetStartY = padding + Math.max(0, (sourceSpanHeight - targetBlockHeight) / 2);
-  } else if (targetAlignMode === 'bottom') {
-    targetStartY = padding + Math.max(0, sourceSpanHeight - targetBlockHeight);
-  } else if (targetAlignMode === 'top') {
-    targetStartY = padding;
-  }
+  const nodePositionMap = {};
+  const nodes = [];
+  columns.forEach((names, depth) => {
+    const blockHeight = columnBlockHeightMap[depth] || 0;
+    const columnGap = columnGapMap[depth] || 0;
+    let startY = padding;
+    if (depth === maxDepth) {
+      if (targetAlignMode === 'middle') {
+        startY = padding + Math.max(0, (sourceSpanHeight - blockHeight) / 2);
+      } else if (targetAlignMode === 'bottom') {
+        startY = padding + Math.max(0, sourceSpanHeight - blockHeight);
+      }
+    }
 
-  const targetPos = {};
-  let targetCursorY = targetStartY;
-  targetNames.forEach((name) => {
-    const nodeHeight = targetValueMap[name] * targetUnitHeight;
-    targetPos[name] = { y: targetCursorY, h: nodeHeight };
-    targetCursorY += nodeHeight + targetGap;
+    let cursorY = startY;
+    const nodeX = leftX + columnStep * depth;
+    names.forEach((name) => {
+      const nodeHeight = (nodeValueMap[name] || 0) * unitHeight;
+      const node = {
+        name,
+        depth,
+        x: nodeX,
+        y: cursorY,
+        h: nodeHeight,
+        colorIndex: Number.isFinite(nodeColorIndexMap[name]) ? nodeColorIndexMap[name] : 0
+      };
+      nodes.push(node);
+      nodePositionMap[name] = node;
+      cursorY += nodeHeight + columnGap;
+    });
   });
 
-  const sourceOffset = {};
-  const targetOffset = {};
-  sourceNames.forEach((name) => {
-    sourceOffset[name] = 0;
-  });
-  targetNames.forEach((name) => {
-    targetOffset[name] = 0;
+  const sourceOffsetMap = {};
+  const targetOffsetMap = {};
+  nodeNames.forEach((name) => {
+    sourceOffsetMap[name] = 0;
+    targetOffsetMap[name] = 0;
   });
 
   const linkSegments = [];
-  links.forEach((link) => {
-    const sourceNode = sourcePos[link.source];
-    const targetNode = targetPos[link.target];
+  validLinks.forEach((link) => {
+    const sourceNode = nodePositionMap[link.source];
+    const targetNode = nodePositionMap[link.target];
     if (!sourceNode || !targetNode) {
       return;
     }
 
-    const linkHeight = Number(link.value || 0) * sourceUnitHeight;
+    const linkHeight = link.value * unitHeight;
     if (linkHeight <= 0) {
       return;
     }
-    const sy = sourceNode.y + sourceOffset[link.source] + linkHeight / 2;
-    const ty = targetNode.y + targetOffset[link.target] + linkHeight / 2;
-    sourceOffset[link.source] += linkHeight;
-    targetOffset[link.target] += linkHeight;
 
-    const startX = leftX + nodeWidth;
-    const endX = rightX;
-    const controlX = (startX + endX) / 2;
+    const sy = sourceNode.y + sourceOffsetMap[link.source] + linkHeight / 2;
+    const ty = targetNode.y + targetOffsetMap[link.target] + linkHeight / 2;
+    sourceOffsetMap[link.source] += linkHeight;
+    targetOffsetMap[link.target] += linkHeight;
+
+    const startX = sourceNode.x + nodeWidth;
+    const endX = targetNode.x;
+    const distance = endX - startX;
+    if (distance <= 0) {
+      return;
+    }
+    const controlOffset = distance * 0.45;
 
     linkSegments.push({
       startX,
       endX,
-      controlX,
+      controlX1: startX + controlOffset,
+      controlX2: endX - controlOffset,
       sy,
       ty,
       linkHeight,
-      sourceIndex: Number.isFinite(nodeColorIndexMap[link.source]) ? nodeColorIndexMap[link.source] : 0
+      sourceIndex: sourceNode.colorIndex
     });
   });
 
   return {
-    leftX,
-    rightX,
     nodeWidth,
-    sourceNames,
-    targetNames,
-    sourcePos,
-    targetPos,
+    maxDepth,
+    nodes,
     nodeColorIndexMap,
     linkSegments
   };
@@ -535,8 +678,8 @@ function buildSankeySvgText(links, width, height, renderOptions) {
 
   layout.linkSegments.forEach((segment) => {
     const pathData = `M ${formatSvgNumber(segment.startX)} ${formatSvgNumber(segment.sy)} C ${formatSvgNumber(
-      segment.controlX
-    )} ${formatSvgNumber(segment.sy)} ${formatSvgNumber(segment.controlX)} ${formatSvgNumber(segment.ty)} ${formatSvgNumber(
+      segment.controlX1
+    )} ${formatSvgNumber(segment.sy)} ${formatSvgNumber(segment.controlX2)} ${formatSvgNumber(segment.ty)} ${formatSvgNumber(
       segment.endX
     )} ${formatSvgNumber(segment.ty)}`;
     segments.push(
@@ -549,51 +692,31 @@ function buildSankeySvgText(links, width, height, renderOptions) {
     );
   });
 
-  layout.sourceNames.forEach((name, index) => {
-    const node = layout.sourcePos[name];
-    const colorIndex = Number.isFinite(layout.nodeColorIndexMap[name])
-      ? layout.nodeColorIndexMap[name]
-      : index;
+  layout.nodes.forEach((node) => {
+    const isSource = node.depth === 0;
+    const isTarget = node.depth === layout.maxDepth;
     const textY = getClampedLabelY(
       node.y,
       node.h,
       height,
       clampNumber(renderOptions && renderOptions.chartPadding, 0, 120, 16)
     );
-    const textPlacement = getSvgLabelPlacement(layout, true, labelPositionMode);
+    const textPlacement = getSvgLabelPlacement(
+      node.x,
+      layout.nodeWidth,
+      isSource,
+      isTarget,
+      labelPositionMode
+    );
     segments.push(
-      `<rect x="${formatSvgNumber(layout.leftX)}" y="${formatSvgNumber(node.y)}" width="${formatSvgNumber(
+      `<rect x="${formatSvgNumber(node.x)}" y="${formatSvgNumber(node.y)}" width="${formatSvgNumber(
         layout.nodeWidth
-      )}" height="${formatSvgNumber(node.h)}" fill="${getNodeColor(colorIndex, themeColors)}" />`
+      )}" height="${formatSvgNumber(node.h)}" fill="${getNodeColor(node.colorIndex, themeColors)}" />`
     );
     segments.push(
       `<text x="${formatSvgNumber(textPlacement.x)}" y="${formatSvgNumber(textY)}" fill="#4e5969" font-size="10" text-anchor="${
         textPlacement.textAnchor
-      }" dominant-baseline="middle">${escapeSvgText(name)}</text>`
-    );
-  });
-
-  layout.targetNames.forEach((name, index) => {
-    const node = layout.targetPos[name];
-    const colorIndex = Number.isFinite(layout.nodeColorIndexMap[name])
-      ? layout.nodeColorIndexMap[name]
-      : index;
-    const textY = getClampedLabelY(
-      node.y,
-      node.h,
-      height,
-      clampNumber(renderOptions && renderOptions.chartPadding, 0, 120, 16)
-    );
-    const textPlacement = getSvgLabelPlacement(layout, false, labelPositionMode);
-    segments.push(
-      `<rect x="${formatSvgNumber(layout.rightX)}" y="${formatSvgNumber(node.y)}" width="${formatSvgNumber(
-        layout.nodeWidth
-      )}" height="${formatSvgNumber(node.h)}" fill="${getNodeColor(colorIndex, themeColors)}" />`
-    );
-    segments.push(
-      `<text x="${formatSvgNumber(textPlacement.x)}" y="${formatSvgNumber(textY)}" fill="#4e5969" font-size="10" text-anchor="${
-        textPlacement.textAnchor
-      }" dominant-baseline="middle">${escapeSvgText(name)}</text>`
+      }" dominant-baseline="middle">${escapeSvgText(node.name)}</text>`
     );
   });
 
@@ -1270,9 +1393,9 @@ Page({
         ctx.beginPath();
         ctx.moveTo(segment.startX, segment.sy);
         ctx.bezierCurveTo(
-          segment.controlX,
+          segment.controlX1,
           segment.sy,
-          segment.controlX,
+          segment.controlX2,
           segment.ty,
           segment.endX,
           segment.ty
@@ -1280,36 +1403,24 @@ Page({
         ctx.stroke();
       });
 
-      layout.sourceNames.forEach((name, index) => {
-        const node = layout.sourcePos[name];
-        const labelPlacement = getCanvasLabelPlacement(layout, true, this.data.labelPositionMode);
-        const colorIndex = Number.isFinite(layout.nodeColorIndexMap[name])
-          ? layout.nodeColorIndexMap[name]
-          : index;
+      layout.nodes.forEach((node) => {
+        const isSource = node.depth === 0;
+        const isTarget = node.depth === layout.maxDepth;
+        const labelPlacement = getCanvasLabelPlacement(
+          node.x,
+          layout.nodeWidth,
+          isSource,
+          isTarget,
+          this.data.labelPositionMode
+        );
         const textY = getClampedLabelY(node.y, node.h, height, this.data.chartPadding);
-        ctx.setFillStyle(getNodeColor(colorIndex, themeColors));
-        ctx.fillRect(layout.leftX, node.y, layout.nodeWidth, node.h);
+        ctx.setFillStyle(getNodeColor(node.colorIndex, themeColors));
+        ctx.fillRect(node.x, node.y, layout.nodeWidth, node.h);
         ctx.setFillStyle('#4e5969');
         ctx.setFontSize(10);
         ctx.setTextAlign(labelPlacement.textAlign);
         ctx.setTextBaseline('middle');
-        ctx.fillText(name, labelPlacement.x, textY);
-      });
-
-      layout.targetNames.forEach((name, index) => {
-        const node = layout.targetPos[name];
-        const labelPlacement = getCanvasLabelPlacement(layout, false, this.data.labelPositionMode);
-        const colorIndex = Number.isFinite(layout.nodeColorIndexMap[name])
-          ? layout.nodeColorIndexMap[name]
-          : index;
-        const textY = getClampedLabelY(node.y, node.h, height, this.data.chartPadding);
-        ctx.setFillStyle(getNodeColor(colorIndex, themeColors));
-        ctx.fillRect(layout.rightX, node.y, layout.nodeWidth, node.h);
-        ctx.setFillStyle('#4e5969');
-        ctx.setFontSize(10);
-        ctx.setTextAlign(labelPlacement.textAlign);
-        ctx.setTextBaseline('middle');
-        ctx.fillText(name, labelPlacement.x, textY);
+        ctx.fillText(node.name, labelPlacement.x, textY);
       });
 
       ctx.draw();