diff --git a/library/think/db/Query.php b/library/think/db/Query.php
index 75086bc6..ac4adea1 100644
--- a/library/think/db/Query.php
+++ b/library/think/db/Query.php
@@ -54,7 +54,7 @@ class Query
     // 回调事件
     private static $event = [];
     // 读取主库
-    private static $readMaster = [];
+    protected static $readMaster = [];
 
     /**
      * 构造函数