diff --git a/PcAtChipsetPkg/PcatRealTimeClockRuntimeDxe/PcRtc.c b/PcAtChipsetPkg/PcatRealTimeClockRuntimeDxe/PcRtc.c
index 35eb60ade4..77ac78d67a 100644
--- a/PcAtChipsetPkg/PcatRealTimeClockRuntimeDxe/PcRtc.c
+++ b/PcAtChipsetPkg/PcatRealTimeClockRuntimeDxe/PcRtc.c
@@ -575,7 +575,7 @@ PcRtcSetWakeupTime (
   UINT8                 Century;
   EFI_TIME_CAPABILITIES Capabilities;
 
-  ZeroMem (RtcTime);
+  ZeroMem (&RtcTime, sizeof (RtcTime));
 
   if (Enable) {