diff --git a/app/controllers/application_controller.rb b/app/controllers/application_controller.rb
index 275d854b..b137fd23 100644
--- a/app/controllers/application_controller.rb
+++ b/app/controllers/application_controller.rb
@@ -158,10 +158,14 @@ class ApplicationController < ActionController::Base
     elsif (@site.default_locale.present? && @site.enable_language_detection.eql?(false))
       default_locale = @site.default_locale
       condition = @site.in_use_locales.include?(default_locale)
-    elsif (@site.enable_language_detection.eql?(true))
+    elsif (@site.enable_language_detection.eql?(true) && @site.default_locale.nil?)
       #check enable langauge detection
       browser_locale = request.env['HTTP_ACCEPT_LANGUAGE'].scan(/^[a-z]{2}/).first rescue nil
-      condition = @site.in_use_locales.include?(browser_locale)
+      if browser_locale.eql?("zh")
+        condition = @site.in_use_locales.include?("zh_tw")
+      else
+        condition = @site.in_use_locales.include?(browser_locale)
+      end
     elsif (@site.default_locale.nil? && @site.enable_language_detection.eql?(false))
       backup_locale = @site.valid_locales.first
       condition = @site.in_use_locales.include?(backup_locale)