procedure TForm1.btn1Click(Sender: TObject);

var

  IdHTTP: TIdHTTP;

  mstrCookie: string;

  Cookies : TIdCookieManager;

  i: Integer;

begin

  IdHTTP := TIdHTTP.Create(nil);

  IdHTTP.Request.UserAgent := '';

  mstrCookie := 'aaa=5555&bb=12345';

  IdHTTP.Request.AcceptEncoding := '';

  if mstrCookie <> '' then

  begin

    IdHTTP.Request.SetHeaders; //说要加这一句。

    IdHTTP.Request.CustomHeaders.Add('Cookie: ' + mstrCookie); 

  end;

  IdHTTP.AllowCookies := True;

  Cookies := TIdCookieManager.Create(nil);

  IdHTTP.HandleRedirects := True;

  IdHTTP.CookieManager := Cookies;

  IdHTTP.ReadTimeout := 25000; //设置读取超时

  Memo1.text := IdHTTP.Get('http://www.baidu.com/');

   mstrCookie:='';

  //Memo1.Lines.Add (Cookies.CookieCollection.Items[0].CookieText); 

  for i := 0 to Cookies.CookieCollection.Count - 1 do

  begin

    Memo1.Lines.Add(Cookies.CookieCollection.Items[i].CookieName + 'Value：' + Cookies.CookieCollection.Items[i].Value);

    mstrCookie:=mstrCookie+  Cookies.CookieCollection.Items[i].CookieName+'='+  Cookies.CookieCollection.Items[i].Value +'&';

  end;

    Memo1.Lines.Add ( mstrCookie);

  IdHTTP.free;

end;