diff --git a/md5.go b/md5.go
index ee270fb..33e9176 100755
--- a/md5.go
+++ b/md5.go
@@ -28,7 +28,7 @@ func Md5Str(str ...string) string {
 
 	var build strings.Builder
 	if len(str) > 0 {
-		for _, v := range rand {
+		for _, v := range str {
 			build.WriteString(v)
 		}
 	} else {