How can I get Great Wall by public bus?

Which section of Great Wall do you plan to visit? Badaling? Mutianyu?

Oh, sorry. I meant Mutianyu wall.

Metro Line10 - No.936 Bus - h23 Bus, about 5.5 hours.

Take the Metro Line 10 at Shuangjing Station, and then get off at Sanyuanqiao Station. Get out of the subway from C1 gate, then walk about 250 meters at Sanyuanqiao Bus Station to take the No.936 Bus and get off at Jiayuan Station where you need to transfer to bus line h23/ h24/ h35/h36 to Mutianyu Roundabout. Afterwards, walk about 450 meters to the ticket office of the scenic area.

Hope to be helpful! Nice trip in Beijing.

Thank you a lot, Kenneth!
G.