diff --git a/MdeModulePkg/Application/CapsuleApp/CapsuleDump.c b/MdeModulePkg/Application/CapsuleApp/CapsuleDump.c
index 26ad60ce59..7605153e97 100644
--- a/MdeModulePkg/Application/CapsuleApp/CapsuleDump.c
+++ b/MdeModulePkg/Application/CapsuleApp/CapsuleDump.c
@@ -632,6 +632,7 @@ SplitFileNameExtension (
 
 **/
 INTN
+EFIAPI
 CompareFileNameInAlphabet (
   IN VOID  *Left,
   IN VOID  *Right