diff --git a/README.md b/README.md
index 72cf428..2ada220 100644
--- a/README.md
+++ b/README.md
@@ -44,7 +44,8 @@ const NODE_SIZE = 16;
 const PEM = 5;
 const ctx = document.getElementById('id-of-canvas-element').getContext('2d');
 const rootNode = Hierarchy.compactBox(root, {
-  direction: 'H', // H / V / LR / RL / TB / BT
+  direction: 'H', // H / V / LR / RL / TB / BT,
+  forceCompact: true, // 开启强制紧凑，节点会以最小宽度和最小高度排列，不论节点在布局过程中是否重叠都会执行子树移动的行为
   getId(d) {
     return d.id;
   },
diff --git a/src/layout/non-layered-tidy.js b/src/layout/non-layered-tidy.js
index 24e9c89..4470ab9 100644
--- a/src/layout/non-layered-tidy.js
+++ b/src/layout/non-layered-tidy.js
@@ -93,6 +93,7 @@ function layer(node, isHorizontal, d = 0) {
 
 module.exports = (root, options = {}) => {
   const isHorizontal = options.isHorizontal;
+  const forceCompact = options.forceCompact;
   function firstWalk(t) {
     if (t.cs === 0) {
       setExtremes(t);
@@ -103,7 +104,7 @@ module.exports = (root, options = {}) => {
     for (let i = 1; i < t.cs; ++i) {
       firstWalk(t.c[i]);
       const min = bottom(t.c[i].er);
-      separate(t, i, ih);
+      separate(t, i, ih, forceCompact);
       ih = updateIYL(min, i, ih);
     }
     positionRoot(t);
@@ -123,7 +124,7 @@ module.exports = (root, options = {}) => {
     }
   }
 
-  function separate(t, i, ih) {
+  function separate(t, i, ih, forceCompact) {
     let sr = t.c[i - 1];
     let mssr = sr.mod;
     let cl = t.c[i];
@@ -131,7 +132,8 @@ module.exports = (root, options = {}) => {
     while (sr !== null && cl !== null) {
       if (bottom(sr) > ih.low) ih = ih.nxt;
       const dist = (mssr + sr.prelim + sr.w) - (mscl + cl.prelim);
-      if (dist > 0) {
+      // if forceCompact, the moveSubTree method is executed no matter what
+      if (forceCompact || dist > 0) {
         mscl += dist;
         moveSubtree(t, i, ih.index, dist);
       }