Take bus No.804 outside the airport to Shiyang Bus Station, then transfer to bus 1 1 to Ximen Station (or Yingmen), and then take bus No.221to Xihua.

You can also take bus No.804 or 3 B outside the airport to Shuangliu Bus Station, then take bus at Jinsha Station, and then take bus No.320 to Xihua.

There are many routes that can provide these two more acceptable.