diff --git a/problems/0617.合并二叉树.md b/problems/0617.合并二叉树.md
index 848454de..ce37a953 100644
--- a/problems/0617.合并二叉树.md
+++ b/problems/0617.合并二叉树.md
@@ -312,7 +312,23 @@ class Solution {
 ```
 
 Python：
-
+```python
+# Definition for a binary tree node.
+# class TreeNode:
+#     def __init__(self, val=0, left=None, right=None):
+#         self.val = val
+#         self.left = left
+#         self.right = right
+//递归法*前序遍历
+class Solution:
+    def mergeTrees(self, root1: TreeNode, root2: TreeNode) -> TreeNode:
+        if not root1: return root2  // 如果t1为空，合并之后就应该是t2
+        if not root2: return root1  // 如果t2为空，合并之后就应该是t1
+        root1.val = root1.val + root2.val  //中
+        root1.left = self.mergeTrees(root1.left , root2.left)  //左
+        root1.right = self.mergeTrees(root1.right , root2.right)  //右
+        return root1  //root1修改了结构和数值
+```
 
 Go：
 
@@ -323,4 +339,4 @@ Go：
 * 作者微信：[程序员Carl](https://mp.weixin.qq.com/s/b66DFkOp8OOxdZC_xLZxfw)
 * B站视频：[代码随想录](https://space.bilibili.com/525438321)
 * 知识星球：[代码随想录](https://mp.weixin.qq.com/s/QVF6upVMSbgvZy8lHZS3CQ)
-<div align="center"><img src=../pics/公众号.png width=450 alt=> </img></div>
\ No newline at end of file
+<div align="center"><img src=../pics/公众号.png width=450 alt=> </img></div>