diff --git a/YD_AllHeartRates.Api/Services/Impl/LargeScreenService.cs b/YD_AllHeartRates.Api/Services/Impl/LargeScreenService.cs
index 7facd7e..e39bcbe 100644
--- a/YD_AllHeartRates.Api/Services/Impl/LargeScreenService.cs
+++ b/YD_AllHeartRates.Api/Services/Impl/LargeScreenService.cs
@@ -127,7 +127,7 @@ namespace YD_AllHeartRates.Api.Services.Impl
             var studentList = _caching.Get<List<StudentDto>>(studentListKey);
 
             // 3. 如果缓存没有 → 查询数据库 + 写入缓存
-            if (studentList == null)
+            if (studentList == null || studentList.Count == 0)
             {
                 studentList = await _sportsContext.Student
                     .Where(x => x.ClassId == classId && x.SchoolCode == schoolCode && x.StudentStatus == 1)