diff --git a/problems/0020.有效的括号.md b/problems/0020.有效的括号.md
index b44d21ed..c3ff9d53 100644
--- a/problems/0020.有效的括号.md
+++ b/problems/0020.有效的括号.md
@@ -400,6 +400,37 @@ bool isValid(char * s){
     return !stackTop;
 }
 ```
+
+
+PHP:
+```php
+// https://www.php.net/manual/zh/class.splstack.php
+class Solution
+{
+    function isValid($s){
+        $stack = new SplStack();
+        for ($i = 0; $i < strlen($s); $i++) {
+            if ($s[$i] == "(") {
+                $stack->push(')');
+            } else if ($s[$i] == "{") {
+                $stack->push('}');
+            } else if ($s[$i] == "[") {
+                $stack->push(']');
+            // 2、遍历匹配过程中，发现栈内没有要匹配的字符 return false
+            // 3、遍历匹配过程中，栈已为空，没有匹配的字符了，说明右括号没有找到对应的左括号 return false
+            } else if ($stack->isEmpty() || $stack->top() != $s[$i]) {
+                return false;
+            } else {//$stack->top() == $s[$i]
+                $stack->pop();
+            }
+        }
+        // 1、遍历完，但是栈不为空,说明有相应的括号没有被匹配,return false
+        return $stack->isEmpty();
+    }
+}
+```
+
+
 Scala:
 ```scala
 object Solution {
@@ -422,5 +453,6 @@ object Solution {
   }
 }
 ```
+
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