diff --git a/app/controllers/concerns/git_helper.rb b/app/controllers/concerns/git_helper.rb
index db99f9da5..f97a137bb 100644
--- a/app/controllers/concerns/git_helper.rb
+++ b/app/controllers/concerns/git_helper.rb
@@ -25,7 +25,7 @@ module GitHelper
         decode_content =
             if cd["encoding"] == 'GB18030' && cd['confidence'] > 0.8
               content.encode('UTF-8', 'GBK', {:invalid => :replace, :undef => :replace, :replace => ' '})
-            elsif cd['encoding'].blank?
+            elsif cd['encoding'].blank? && !content.blank?
               raise("ERROR_UTF8")
             else
               content.force_encoding('UTF-8')
@@ -36,7 +36,7 @@ module GitHelper
 
     rescue Exception => e
       Rails.logger.error(e.message)
-      error_msg = e.message == "ERROR_UTF8" ? "文件无法预览" : "文档内容获取异常"
+      error_msg = e.message == "ERROR_UTF8" ? "文件编码异常，请将文件编码设置为UTF-8" : "文档内容获取异常"
       error_status =  e.message == "ERROR_UTF8" ? -2 : -1
       raise Educoder::TipException.new(error_status, error_msg)
     end