Please advise me bus from Chao Yang District in Beijing to Badaling Great Walls.

Rendi, since you didn't tell where exactly you were in Chaoyang district, I couldn't give very detailed information. You should figure out to take subway line 2 and get off at Jishuitan Station. Then you need to walk to Deshengmen. There you can take no.877 bus to reach the wall. There are many drivers who might stop you when you walk to Deshenmen. Some of them may tell that it takes 3 to 4 hours to take bus from Deshengmen to the wall. Don't believe them.