diff --git a/src/lang.rs b/src/lang.rs
index d44e4215c..27f2b6939 100644
--- a/src/lang.rs
+++ b/src/lang.rs
@@ -83,16 +83,17 @@ pub const LANGS: &[(&str, &str)] = &[
 
 #[cfg(not(any(target_os = "android", target_os = "ios")))]
 pub fn translate(name: String) -> String {
-    let locale = sys_locale::get_locale().unwrap_or_default().to_lowercase();
+    let locale = sys_locale::get_locale().unwrap_or_default();
     translate_locale(name, &locale)
 }
 
 pub fn translate_locale(name: String, locale: &str) -> String {
+    let locale = locale.to_lowercase();
     let mut lang = hbb_common::config::LocalConfig::get_option("lang").to_lowercase();
     if lang.is_empty() {
         // zh_CN on Linux, zh-Hans-CN on mac, zh_CN_#Hans on Android
         if locale.starts_with("zh") {
-            lang = (if locale.contains("TW") {
+            lang = (if locale.contains("tw") {
                 "zh-tw"
             } else {
                 "zh-cn"