Badaling great wall from novotel peace beijing by subway or by bus or both?

Generally, both bus and subway are needed. However, as your mother uses wheelchair, it is not that convenient to take bus. Considering all, I'd suggest you take a taxi to reach for all convenience. To rent a taxi for the wall for a round trip, the charge is CNY400-500.

thanks for fast reply. may i know, how to get this section from novotel peace by bus or by train or both?

By bus: you can walk south from your hotel to find Jinyu Hutong and then walk around 209 meters to find Dongdanbeidajie, turn left and walk north to find Dengshikou station of subway line 5. Take subway line 5 to get off at Yonghegong station. Then go through the underground to find the A entrance of subway line 2, get out and walk toward east to find Yonghegongqiaodongzhan bus station. Here you can take bus no. 909 to reach Deshengmen. There you can take bus no. 877 to reach the Wall.

By train: use the above route to take subway line 5 to Yonghegong, change line 2 to Xizhimen station. Then get out from E1 Entrance to reach Beijing North Railway Station. Here you can take S2 train to Badaling. Please understand that passengers don’t take seat according to their tickets. If you plan to take a seat, then board the train as early as you can.