diff --git a/src/dataANDcalc/java/tree/TreeIterator.java b/src/dataANDcalc/java/tree/TreeIterator.java
new file mode 100644
index 0000000..e53613a
--- /dev/null
+++ b/src/dataANDcalc/java/tree/TreeIterator.java
@@ -0,0 +1,120 @@
+package tree;
+
+public class TreeIterator {
+
+    private TreeNode root;
+
+    private void transTree(int[] arr){
+       for (int i = 0; i < arr.length; i++) {
+           TreeNode treeNode = new TreeNode(arr[i]);
+           addNode(root, treeNode);
+       }
+    }
+
+    private void addNode(TreeNode tempNode, TreeNode treeNode){
+        if(root == null){
+            root = treeNode;
+            return;
+        }
+
+        if(treeNode.node<tempNode.node){
+            if (tempNode.left == null){
+                tempNode.left = treeNode;
+            } else {
+                addNode(tempNode.left, treeNode);
+            }
+        }
+
+        if(treeNode.node>tempNode.node){
+            if (tempNode.right == null){
+                tempNode.right = treeNode;
+            } else {
+                addNode(tempNode.right, treeNode);
+            }
+        }
+    }
+
+    private void forwardIterator(TreeNode treeNode){
+        if(treeNode == null){
+            System.out.println("当前节点为空");
+            return;
+        }
+
+        System.out.println(treeNode.toString());
+
+        if (treeNode.left != null){
+            forwardIterator(treeNode.left);
+        }
+
+        if (treeNode.right!= null){
+            forwardIterator(treeNode.right);
+        }
+    }
+
+    private void middleIterator(TreeNode treeNode){
+        if(treeNode == null){
+            System.out.println("当前节点为空");
+            return;
+        }
+
+        if (treeNode.left!= null){
+            middleIterator(treeNode.left);
+        }
+
+        System.out.println(treeNode.toString());
+
+        if (treeNode.right!= null){
+            middleIterator(treeNode.right);
+        }
+    }
+
+    private void behindIteratro(TreeNode treeNode){
+        if(treeNode == null){
+            System.out.println("当前节点为空");
+            return;
+        }
+
+        if (treeNode.left!= null){
+            behindIteratro(treeNode.left);
+        }
+
+        if (treeNode.right!= null){
+            behindIteratro(treeNode.right);
+        }
+
+        System.out.println(treeNode.toString());
+    }
+
+    public static class TreeNode{
+        private int node;
+
+        private TreeNode left;
+
+        private TreeNode right;
+
+        public TreeNode(int node) {
+            this.node = node;
+        }
+
+        @Override
+        public String toString() {
+            return "TreeNode{" +
+                    "node=" + node +
+                    ", left=" + (left == null ? "null" : left.node) +
+                    ", right=" + (right == null ? "null" : right.node) +
+                    '}';
+        }
+    }
+
+    public static void main(String[] args) {
+        int[] arr = {7, 3, 10, 12, 5, 1, 9};
+        TreeIterator treeIterator = new TreeIterator();
+        treeIterator.transTree(arr);
+        System.out.println("前序遍历:");
+        treeIterator.forwardIterator(treeIterator.root);
+        System.out.println("中序遍历:");
+        treeIterator.middleIterator(treeIterator.root);
+        System.out.println("后序遍历:");
+        treeIterator.behindIteratro(treeIterator.root);
+    }
+}