diff --git a/src/main/java/com/gxwebsoft/common/system/controller/MainController.java b/src/main/java/com/gxwebsoft/common/system/controller/MainController.java
index eaebab6..459c32e 100644
--- a/src/main/java/com/gxwebsoft/common/system/controller/MainController.java
+++ b/src/main/java/com/gxwebsoft/common/system/controller/MainController.java
@@ -754,14 +754,8 @@ public class MainController extends BaseController {
     if (!StrUtil.equals(code, cacheClient.get(phone, String.class))) {
       throw new BusinessException("验证码不正确");
     }
-    // 注册管理员
-    final UserParam param = new UserParam();
-    param.setPhone(phone);
-    param.setTemplateId(user.getTemplateId());
-    param.setIsAdmin(true);
-    if (userService.getAdminByPhone(param) != null) {
-      throw new BusinessException("该手机号码已注册");
-    }
+    // 注册管理员（已去掉手机号唯一限制，同一手机号可创建多个租户）
+    // 重复注册的检查由数据库唯一约束处理
 
     // 验证租户名称是否重复
     if (StrUtil.isNotBlank(tenantName)) {
@@ -924,14 +918,8 @@ public class MainController extends BaseController {
     if (!StrUtil.equals(code, cacheClient.get(phone, String.class)) && !StrUtil.equals(code, redisUtil.get(CACHE_KEY_VERIFICATION_CODE_BY_DEV_SMS))) {
       throw new BusinessException("验证码不正确");
     }
-    // 注册管理员
-    final UserParam param = new UserParam();
-    param.setPhone(phone);
-    param.setIsAdmin(true);
-    param.setTemplateId(user.getTemplateId());
-    if (userService.getAdminByPhone(param) != null) {
-      throw new BusinessException("该手机号码已注册");
-    }
+    // 注册管理员（已去掉手机号唯一限制，同一手机号可创建多个租户）
+    // 重复注册的检查由数据库唯一约束处理
 
     // 验证租户名称是否重复
     if (StrUtil.isNotBlank(tenantName)) {
diff --git a/src/main/java/com/gxwebsoft/common/system/mapper/xml/UserMapper.xml b/src/main/java/com/gxwebsoft/common/system/mapper/xml/UserMapper.xml
index 374314a..4031414 100644
--- a/src/main/java/com/gxwebsoft/common/system/mapper/xml/UserMapper.xml
+++ b/src/main/java/com/gxwebsoft/common/system/mapper/xml/UserMapper.xml
@@ -316,7 +316,7 @@
     WHERE user_id = #{userId}
   </select>
 
-  <!-- 根据手机号码查询 -->
+  <!-- 根据手机号码查询（支持多租户：必须传 tenantId 才能查到对应租户的管理员） -->
   <select id="selectAdminByPhone" resultType="com.gxwebsoft.common.system.entity.User">
     SELECT a.*
     FROM sys_user a
@@ -324,9 +324,7 @@
       AND a.deleted = 0
       AND a.phone = #{param.phone}
       AND (a.username = 'superAdmin' OR a.username = 'admin' OR a.is_admin = 1)
-      <if test="param.tenantId">
-        AND a.tenant_id = #{param.tenantId}
-      </if>
+      AND a.tenant_id = #{param.tenantId}
       LIMIT 1
     </where>
   </select>