diff --git a/src/main/java/cx/by/HappyTree/TreeNode.java b/src/main/java/cx/by/HappyTree/TreeNode.java
index d4cae5a..f3865c3 100644
--- a/src/main/java/cx/by/HappyTree/TreeNode.java
+++ b/src/main/java/cx/by/HappyTree/TreeNode.java
@@ -43,7 +43,7 @@ public boolean setParent(Object node) {
             this.parent = node;
             Object tmp  = node;
             while (null != ((TreeNode) tmp).parent()){
-                tmp = root.parent();
+                tmp = ((TreeNode) tmp).parent();
             }
             if(tmp instanceof HappyTree)
                 root = (HappyTree) tmp;
@@ -80,8 +80,6 @@ public ArrayList<TreeNode> getAllChild() {
                 resList.add((TreeNode) node);
             }
             return resList;
-        }else {
-
         }
         return null;
     }
@@ -94,8 +92,6 @@ public ArrayList<TreeNode> getAllChild(TreeNode current) {
                 resList.add((TreeNode) node);
             }
             return resList;
-        }else {
-
         }
         return null;
     }
@@ -141,9 +137,16 @@ public boolean addChild(Object... node) {
                 for (TreeNode tree:children) {
                     if(maxLen<tree.length())maxLen=tree.length();
                 }
-                for(int i = -1; i<(((TreeNode) item).length()-maxLen);i++){
-                    incrLength();
+                if(parent!=null&&((parent().length-this.length)==1||(parent().length-this.length)<=maxLen)){
+                    for(int i = -1; i<(((TreeNode) item).length()-maxLen);i++){
+                        incrLength();
+                    }
+                }else {
+                    for(int i = -1; i<(((TreeNode) item).length()-maxLen);i++){
+                        length++;
+                    }
                 }
+
                 children.add((TreeNode) item);
                 ((TreeNode)item).setParent(this);
             }else {
@@ -204,7 +207,7 @@ public Object contain() {
     @Override
     public void incrLength() {
         length++;
-        if(null!=parent){
+        if(null!=parent()){
             ((TreeNode)parent).incrLength();
         }
     }
diff --git a/src/test/java/MainTest.java b/src/test/java/MainTest.java
index 15e3b64..1926b30 100644
--- a/src/test/java/MainTest.java
+++ b/src/test/java/MainTest.java
@@ -54,8 +54,14 @@ public void A_addChildTest(){
         TestCase.assertNull(node2.getAllChild());
         TestCase.assertNull(node1.getAllChild(node2));
         buildData();
+        TreeNode node2_2 = new TreeNode();
+        node2.addChild(node2_2);
         TestCase.assertEquals(happyTree.length(),5);
         TestCase.assertEquals(happyTree.children().size(),3);
+        TestCase.assertFalse(node2.addChild("asd"));
+        TreeNode node1_1_1_1_1 = new TreeNode();
+        node1_1_1_1.addChild(node1_1_1_1_1);
+        TestCase.assertEquals(happyTree.length(),6);
     }
     @Test
     public void B_getAllChildTest(){
@@ -100,6 +106,7 @@ public void G_getAllChildTest(){
         buildData();
         List<TreeNode>list = node1.getAllChild(node2);
         TestCase.assertEquals(list.size(),1);
+        TestCase.assertEquals(node1.findAll("node1_1").get(0),node1_1);
     }
     @Test
     public void H_clearTest(){
@@ -114,4 +121,10 @@ public void I_splitTest(){
         TestCase.assertEquals(happyTree.split(node1),node1);
         TestCase.assertEquals(happyTree.children().size(),2);
     }
+    @Test
+    public void J_equalTest(){
+        TreeNode node1 = new TreeNode();
+        TreeNode node2 = new TreeNode();
+        TestCase.assertEquals(true,node1.equals(node2));
+    }
 }