diff --git a/pkg/pinyin/mspy_udl.go b/pkg/pinyin/mspy_udl.go
index edded6c..d51da03 100644
--- a/pkg/pinyin/mspy_udl.go
+++ b/pkg/pinyin/mspy_udl.go
@@ -489,7 +489,7 @@ func (f *MspyUDL) Unmarshal(r *bytes.Reader) []*Entry {
 }
 
 func (f *MspyUDL) Marshal(di []*Entry) []byte {
-	slices.DeleteFunc(di, func(v *Entry) bool {
+	di = slices.DeleteFunc(di, func(v *Entry) bool {
 		for _, r := range v.Word {
 			if !unicode.Is(unicode.Han, r) {
 				return true