IDHTTP get 提交数据失败

http://lxdq.张三&Phone=18871216316&Address=张三丰路&Appointment=1224834931&Remark%20=送支架&ItemList=[{"Item":"海信电视","Qty":"2","ItemType":"2","Distribution":"1","Installation":"30"}]
    utf-8码，在IE中测试，提交数据成功，但是在delphi中提交数据失败，急求大侠赐教！代码如下：
var
  HttpClient: TIdHttp;
  ParamList: TStringList;
  SS: TStringStream;
  s: string;
begin
  SS := TStringStream.Create;
  s:= Edit13.text + 'OrderNum' +  '=' +  Edit1.Text +  '&'
  + 'Datetime' +  '=' +  Edit2.Text +  '&'
  + 'Customer' +  '=' +  Edit3.Text +  '&'
  + 'Phone' +  '=' +  Edit4.Text +  '&'
  + 'Address' +  '=' +  Edit5.Text +  '&'
  + 'Appointment' +  '=' +  Edit6.Text +  '&'
  + 'Remark ' +  '=' +  Edit7.Text +  '&'
  + 'ItemList=' + '['
  +'{'+
      Chr(34) + 'Item' + Chr(34) + ':' + Chr(34) + Edit8.Text + Chr(34) + ','+
      Chr(34) + 'Qty' + Chr(34) + ':' + Chr(34) + Edit9.Text + Chr(34) + ','+
      Chr(34) + 'ItemType' + Chr(34) + ':' + Chr(34) + Edit10.Text + Chr(34) + ','+
      Chr(34) + 'Distribution' + Chr(34) + ':' + Chr(34) + Edit11.Text + Chr(34) + ','+
      Chr(34) + 'Installation' + Chr(34) + ':' + Chr(34) + Edit12.Text + Chr(34) +
      '}'+
       ']';
    IdHTTP1.Request.ContentType := 'application/x-www-form-urlencoded';
    IdHTTP1.Request.CharSet := 'utf-8';
    IdHTTP1.Request.ContentEncoding := 'utf-8';
    IdHTTP1.GET(s, SS);
    ShowMessage(SS.DataString);