diff --git a/problems/0530.二叉搜索树的最小绝对差.md b/problems/0530.二叉搜索树的最小绝对差.md
index 87ed222e..903ebf78 100644
--- a/problems/0530.二叉搜索树的最小绝对差.md
+++ b/problems/0530.二叉搜索树的最小绝对差.md
@@ -151,23 +151,27 @@ public:
 
 
 Java：
-```java
-class Solution {
-    private TreeNode pre = null;
-    private int res = Integer.MAX_VALUE;
-    public int getMinimumDifference(TreeNode root) {
-        getMiniDiff(root);
-        return res;
-    }
 
-    private void getMiniDiff (TreeNode root) {
-        if (root == null) return;
-        getMiniDiff(root.left);
+```Java
+class Solution {
+    TreeNode pre;// 记录上一个遍历的结点
+    int result = Integer.MAX_VALUE;
+    public int getMinimumDifference(TreeNode root) {
+        if (root == null) {
+            return result;
+        }
+        // 左
+        int left = getMinimumDifference(root.left);
+        
+        // 中
         if (pre != null) {
-            res = Math.min(root.val - pre.val,res);
+            result = Math.min(left, root.val - pre.val);
         }
         pre = root;
-        getMiniDiff(root.right);
+        // 右
+        int right = getMinimumDifference(root.right);
+        result = Math.min(right, result);
+        return result;
     }
 }
 ```