Response.Charset ="gb2312";
Response.Buffer =true;
Response.AddHeader("content-disposition", "attachment;filename="+ HttpUtility.UrlEncode("用户信息表.xls").ToString());
Response.ContentType ="application/ms-excel";
Response.Write("<html><head><meta http-equiv=Content-Type content=\"text/html; charset=utf-8\">");
System.IO.StringWriter sw =new System.IO.StringWriter();
HtmlTextWriter hw =new HtmlTextWriter(sw);
this.GridView1.RenderControl(hw);
Response.Write(sw.ToString());
Response.Write("</body></html>");
Response.Flush();
Response.End();
像这样写问题就解决了。