diff --git a/problems/0700.二叉搜索树中的搜索.md b/problems/0700.二叉搜索树中的搜索.md
index bc21bab8..65e69219 100644
--- a/problems/0700.二叉搜索树中的搜索.md
+++ b/problems/0700.二叉搜索树中的搜索.md
@@ -464,6 +464,28 @@ impl Solution {
     }
 }
 ```
+### C#
+```C#
+// 递归
+public TreeNode SearchBST(TreeNode root, int val)
+{
+    if (root == null || root.val == val) return root;
+    if (root.val > val) return SearchBST(root.left, val);
+    if (root.val < val) return SearchBST(root.right, val);
+    return null;
+}
+//  迭代
+public TreeNode SearchBST(TreeNode root, int val)
+{
+    while (root != null)
+    {
+        if (root.val > val) root = root.left;
+        else if (root.val < val) root = root.right;
+        else return root;
+    }
+    return null;
+}
+```
 
 <p align="center">
 <a href="https://programmercarl.com/other/kstar.html" target="_blank">