Ms.DOFR：
There is no subway leading to Badaling Great Wall, but there is train to the Great Wall. It takes you RMB19 for hard seat and RMB 23 for soft seat. The following is the information:
Y563 Beijing North Station starting time 07:26 arrival time 08:25
Y565 Beijing North Station starting time 08:00 arrival time 09:09
Y567 Beijing North Station starting time 09:33 arrival time 10:42
Y571 Beijing North Station starting time 11:08 arrival time 12:15
Y573 Beijing North Station starting time 11:52 arrival time 12:59
Y575 Beijing North Station starting time 13:19 arrival time 14:28
Y579 Beijing North Station starting time 15:01 arrival time 16:10
Y581 Beijing North Station starting time 15:54 arrival time 16:53
Y587 Beijing North Station starting time 19:32 arrival time 20:41

After arriving at Badaling Station, you need to hire a taxi to the spots. Please negotiate fare with the driver.

If you go to Badaling Great Wall, you could take a bus from downtown Beijing to arrive there directly. At Wangfujing, you could take the subway Line 1 and then Line 2 to arrive at Jishuitan station firstly. Exit from the subway station, you could walk eastwards to Deshengmen, where you could take the bus 919 to get to Badaling directly. Here is the details for your reference: https://www.travelchinaguide.com/china_great_wall/scene/beijing/badaling.htm