I'm staying at Jingtailong Int Hotels, please advice best transportation to Badaling Great Wall.

There are direct buses near the Deshengmen Arrow Tower. To get there, it is suggested you walk along the nearby Qianmen Street to Qianmen Subway Station; take line 2 there to Jishuitan Station, then get out from Exit B2 and go eastwards to find the stop of bus no. 877. Take that bus and you will arrive at the Wall in around one hour.