diff --git a/src/think/Validate.php b/src/think/Validate.php
index 078840641539fcb51db56c26aaa4fa61075c840a..281ce236fa6eb539d22cf646561c6fbcdd513dd3 100644
--- a/src/think/Validate.php
+++ b/src/think/Validate.php
@@ -1274,7 +1274,7 @@ class Validate
      */
     public function in($value, $rule): bool
     {
-        return in_array($value, is_array($rule) ? $rule : explode(',', $rule));
+        return in_array($value, is_array($rule) ? $rule : explode(',', $rule), true);
     }
 
     /**