diff --git a/group01/280646174/basic/src/main/java/com/coding2017/basic/BinaryTreeNode.java b/group01/280646174/basic/src/main/java/com/coding2017/basic/BinaryTreeNode.java
index 29910f06a3..acf4798b9e 100644
--- a/group01/280646174/basic/src/main/java/com/coding2017/basic/BinaryTreeNode.java
+++ b/group01/280646174/basic/src/main/java/com/coding2017/basic/BinaryTreeNode.java
@@ -2,19 +2,35 @@
 
 public class BinaryTreeNode {
 
-    private Object data;
+    private Integer data;
     private BinaryTreeNode left;
     private BinaryTreeNode right;
 
-	public BinaryTreeNode insert(Object o) {
-		return null;
+	public BinaryTreeNode insert(Integer o) {
+        if (o <= data) {
+            if (left == null) {
+                left = new BinaryTreeNode(o);
+                return left;
+            }
+            return left.insert(o);
+        } else {
+            if (right == null) {
+                right = new BinaryTreeNode(o);
+                return right;
+            }
+            return right.insert(o);
+        }
 	}
 
-    public Object getData() {
+    public BinaryTreeNode(Integer data) {
+	    this.data = data;
+    }
+
+    public Integer getData() {
         return data;
     }
 
-    public void setData(Object data) {
+    public void setData(Integer data) {
         this.data = data;
     }
 
@@ -34,4 +50,8 @@ public void setRight(BinaryTreeNode right) {
         this.right = right;
     }
 
+    @Override
+    public String toString() {
+        return data + " " + left + " " + right;
+    }
 }
diff --git a/group01/280646174/basic/src/test/java/com/coding2017/basic/BinaryTreeNodeTest.java b/group01/280646174/basic/src/test/java/com/coding2017/basic/BinaryTreeNodeTest.java
new file mode 100644
index 0000000000..3a9877c596
--- /dev/null
+++ b/group01/280646174/basic/src/test/java/com/coding2017/basic/BinaryTreeNodeTest.java
@@ -0,0 +1,24 @@
+package com.coding2017.basic;
+
+import org.junit.Test;
+
+import static org.junit.Assert.*;
+
+/**
+ * Created by kaitao.li on 17/2/24.
+ */
+public class BinaryTreeNodeTest {
+
+    @Test
+    public void insert() throws Exception {
+        BinaryTreeNode binaryTreeNode = new BinaryTreeNode(5);
+        binaryTreeNode.insert(4);
+        binaryTreeNode.insert(6);
+        binaryTreeNode.insert(5);
+        assertTrue(binaryTreeNode.getLeft().getData() == 4);
+        assertTrue(binaryTreeNode.getRight().getData() == 6);
+        assertTrue(binaryTreeNode.getLeft().getRight().getData() == 5);
+        System.out.println(binaryTreeNode);
+    }
+
+}
\ No newline at end of file