diff --git a/FrontendWebApi/ApiControllers/DeviceManageController.cs b/FrontendWebApi/ApiControllers/DeviceManageController.cs
index 8832166..08b7bde 100644
--- a/FrontendWebApi/ApiControllers/DeviceManageController.cs
+++ b/FrontendWebApi/ApiControllers/DeviceManageController.cs
@@ -143,11 +143,20 @@ namespace FrontendWebApi.ApiControllers
                 apiResult.Msg = "必須選擇東別";
                 return apiResult;
             }
+            else if (string.IsNullOrEmpty(fd.sub_system_tag))
+            {
+                apiResult.Code = "0002";
+                apiResult.Msg = "必須選擇小類系統";
+                return apiResult;
+            }
 
             try
             {
-                var sqlString = $@"select full_name as floor_tag from floor where deleted = 0 and building_tag = @building_tag order by priority";
-                var param = new { @building_tag = fd.building_tag };
+                var sqlString = $@"select f.full_name as floor_tag
+                                   from sub_system_floor ssf
+                                   join floor f on ssf.floor_tag = f.full_name and f.deleted = 0
+                                   where ssf.deleted = 0 and f.building_tag = @building_tag and sub_system_tag = @sub_system_tag order by f.priority";
+                var param = new { @building_tag = fd.building_tag, @sub_system_tag = fd.sub_system_tag };
                 var fl = await backendRepository.GetAllAsync<FloorList>(sqlString, param);
 
                 apiResult.Code = "0000";