diff --git a/EdkCompatibilityPkg/Foundation/Framework/Include/PeiApi.h b/EdkCompatibilityPkg/Foundation/Framework/Include/PeiApi.h
index dde93c3204..f438bfbfbe 100644
--- a/EdkCompatibilityPkg/Foundation/Framework/Include/PeiApi.h
+++ b/EdkCompatibilityPkg/Foundation/Framework/Include/PeiApi.h
@@ -482,7 +482,7 @@ EFI_STATUS
 //
 // EFI PEI Services Table
 //
-#define PEI_SERVICES_SIGNATURE  0x5652455320494550
+#define PEI_SERVICES_SIGNATURE  0x5652455320494550ULL
 #define PEI_SERVICES_REVISION   ((PEI_SPECIFICATION_MAJOR_REVISION << 16) | (PEI_SPECIFICATION_MINOR_REVISION))
 typedef PEI_CPU_IO_PPI          EFI_PEI_CPU_IO_PPI;