Taxi: from airport, it will take one hour and cost about RMB 120. from train station, it will take 30 mins and cost about RMB 35.
Subway: we are just in the middle between Xi Si station on line 4 and Fu Cheng Men station on line 4. After walking 10 mins then you can get to the crossing of Zhao Deng Yu Road and Fu Cheng Men Nei street, then turn to north and keep walking 3 mins then can find An Ping Alley.
Chinese address:
北京市西城区赵登禹路安平巷8号