1.使用Server.UrlEncode 此时web.config必须配置<globalization requestEncoding="utf-8" responseEncoding="utf-8"/>
2. 所以不要用Server.UrlEncode，换HttpUtility.UrlEncode
string s=HttpUtility.UrlEncode(System.Text.UTF8Encoding.UTF8.GetBytes("中文"));
Response.AppendHeader("Content-Disposition", "attachment; filename=" + s); 此时,web.config里utf-8或gb2312都可.