diff --git a/MdeModulePkg/Universal/PcatRealTimeClockRuntimeDxe/PcRtc.c b/MdeModulePkg/Universal/PcatRealTimeClockRuntimeDxe/PcRtc.c
index a007bd0595..c9bf401e1c 100644
--- a/MdeModulePkg/Universal/PcatRealTimeClockRuntimeDxe/PcRtc.c
+++ b/MdeModulePkg/Universal/PcatRealTimeClockRuntimeDxe/PcRtc.c
@@ -179,7 +179,7 @@ Returns:
   // Set RTC configuration after get original time
   // The value of bit AIE should be reserved.
   //
-  RtcWrite (RTC_ADDRESS_REGISTER_B, RTC_INIT_REGISTER_B | (RegisterB.Data & BIT5));
+  RtcWrite (RTC_ADDRESS_REGISTER_B, (UINT8)(RTC_INIT_REGISTER_B | (RegisterB.Data & BIT5)));
 
   //
   // Release RTC Lock.