diff --git a/backend/crmeb/module/BaseModuleInstaller.php b/backend/crmeb/module/BaseModuleInstaller.php
index 14306e1f8..fbf2be5a1 100644
--- a/backend/crmeb/module/BaseModuleInstaller.php
+++ b/backend/crmeb/module/BaseModuleInstaller.php
@@ -1608,14 +1608,27 @@ abstract class BaseModuleInstaller implements ModuleInstallerInterface
         );
 
         $database = (string)config('database.connections.mysql.database');
+        // MySQL 5.7 不支持函数索引，改用 STORED 生成列 + 普通唯一索引。
+        // NULLIF 生成 NULL，允许空 key 重复；非空 key 仍由唯一索引约束。
+        $generatedColumn = Db::query(
+            'SELECT 1 FROM information_schema.columns'
+            . ' WHERE table_schema = ? AND table_name = ? AND column_name = ? LIMIT 1',
+            [$database, $fullTable, 'menu_key_unique']
+        );
+        if (empty($generatedColumn)) {
+            Db::execute(
+                "ALTER TABLE `{$fullTable}` ADD COLUMN `menu_key_unique` varchar(190) "
+                . "GENERATED ALWAYS AS (NULLIF(`menu_key`, '')) STORED "
+                . "COMMENT '菜单稳定标识唯一键（空值不参与唯一约束）' AFTER `menu_key`"
+            );
+        }
         $index = Db::query(
             'SELECT 1 FROM information_schema.statistics'
             . ' WHERE table_schema = ? AND table_name = ? AND index_name = ? LIMIT 1',
             [$database, $fullTable, 'uk_menu_key']
         );
         if (empty($index)) {
-            // NULLIF 允许极端中断场景暂存空 key，所有正常写入仍受唯一约束。
-            Db::execute("ALTER TABLE `{$fullTable}` ADD UNIQUE KEY `uk_menu_key` ((NULLIF(`menu_key`, ''))) ");
+            Db::execute("ALTER TABLE `{$fullTable}` ADD UNIQUE KEY `uk_menu_key` (`menu_key_unique`)");
         }
     }
 
diff --git a/backend/public/install/crmeb_table.sql b/backend/public/install/crmeb_table.sql
index 84fb39121..28c80e283 100755
--- a/backend/public/install/crmeb_table.sql
+++ b/backend/public/install/crmeb_table.sql
@@ -1799,6 +1799,7 @@ CREATE TABLE IF NOT EXISTS `eb_system_menus` (
   `is_header` tinyint(1) NOT NULL DEFAULT '0' COMMENT '是否顶部菜单1是0否',
   `unique_auth` varchar(150) NOT NULL DEFAULT '' COMMENT '前台唯一标识',
   `menu_key` varchar(190) NOT NULL DEFAULT '' COMMENT '菜单稳定标识，系统生成且不可修改',
+  `menu_key_unique` varchar(190) GENERATED ALWAYS AS (NULLIF(`menu_key`, '')) STORED COMMENT '菜单稳定标识唯一键（空值不参与唯一约束）',
   `is_del` tinyint(1) NOT NULL DEFAULT '0' COMMENT '是否删除',
   `mark` varchar(500) NOT NULL DEFAULT '' COMMENT '备注',
   `owner_plugin_id` varchar(96) NOT NULL DEFAULT '' COMMENT '所属插件复合标识，空为核心菜单',
@@ -1807,7 +1808,7 @@ CREATE TABLE IF NOT EXISTS `eb_system_menus` (
   KEY `is_show` (`is_show`) USING BTREE,
   KEY `access` (`access`) USING BTREE,
   KEY `idx_owner_plugin_id` (`owner_plugin_id`),
-  UNIQUE KEY `uk_menu_key` ((NULLIF(`menu_key`, '')))
+  UNIQUE KEY `uk_menu_key` (`menu_key_unique`)
 ) ENGINE=InnoDB AUTO_INCREMENT=4961 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci ROW_FORMAT=DYNAMIC COMMENT='菜单表';
 
 -- eb_system_pem：证书表