diff --git a/BaseTools/Source/C/VfrCompile/Pccts/support/set/set.c b/BaseTools/Source/C/VfrCompile/Pccts/support/set/set.c
index eb6fba7393..6b9b510b8a 100644
--- a/BaseTools/Source/C/VfrCompile/Pccts/support/set/set.c
+++ b/BaseTools/Source/C/VfrCompile/Pccts/support/set/set.c
@@ -554,7 +554,7 @@ register char *s;
 	static set a;
 	register unsigned *p, *endp;
 
-	set_new(a, strlen(s));
+	set_new(a, (unsigned) strlen(s));
 	p = a.setword;
 	endp = &(a.setword[a.n]);
 	do {