diff --git a/Service/AlarmService.cs b/Service/AlarmService.cs
index 5d3ab29..dcd8b2a 100644
--- a/Service/AlarmService.cs
+++ b/Service/AlarmService.cs
@@ -266,7 +266,7 @@ namespace LY.App.Service
                     startTime = SqlFunc.AggregateMin(st.CreateTime),
                     endTime = SqlFunc.AggregateMax(st.CreateTime),
                     sn = st.serial_number,
-                    Frequency = SqlFunc.AggregateMax(st.freq),
+                    Frequency = st.freq,
                     duration = (SqlFunc.AggregateMax(st.CreateTime) - SqlFunc.AggregateMin(st.CreateTime)).TotalSeconds,
                     model = st.device_type,
                     positionId = st.positionId,