diff --git a/problems/二叉树的递归遍历.md b/problems/二叉树的递归遍历.md
index f2072e30..68f17257 100644
--- a/problems/二叉树的递归遍历.md
+++ b/problems/二叉树的递归遍历.md
@@ -221,12 +221,12 @@ class Solution:
 Go：
 
 前序遍历:
-```
+```go
 func PreorderTraversal(root *TreeNode) (res []int) {
     var traversal func(node *TreeNode)
     traversal = func(node *TreeNode) {
 	if node == nil {
-        return
+            return
 	}
 	res = append(res,node.Val)
 	traversal(node.Left)
@@ -239,12 +239,12 @@ func PreorderTraversal(root *TreeNode) (res []int) {
 ```
 中序遍历:
 
-```
+```go
 func InorderTraversal(root *TreeNode) (res []int) {
     var traversal func(node *TreeNode)
     traversal = func(node *TreeNode) {
 	if node == nil {
-		return
+	    return
 	}
 	traversal(node.Left)
 	res = append(res,node.Val)
@@ -256,12 +256,12 @@ func InorderTraversal(root *TreeNode) (res []int) {
 ```
 后序遍历:
 
-```
+```go
 func PostorderTraversal(root *TreeNode) (res []int) {
     var traversal func(node *TreeNode)
     traversal = func(node *TreeNode) {
 	if node == nil {
-		return
+	    return
 	}
 	traversal(node.Left)
 	traversal(node.Right)