diff --git a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.c b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.c
index 0a6c872baa..15e55d417e 100644
--- a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.c
+++ b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.c
@@ -426,7 +426,7 @@ SmmVariableHandler (
     return EFI_SUCCESS;
   }
 
-  if (*CommBufferSize < sizeof(SMM_VARIABLE_COMMUNICATE_HEADER) - 1) {
+  if (*CommBufferSize < SMM_VARIABLE_COMMUNICATE_HEADER_SIZE) {
     return EFI_SUCCESS;
   }