We are staying near Dongsi line, which transport should we take to go to Badaling Great Wall?

Take the Metro Line 5 at Dongsi Station and get off at Yonghe Lamasery Station. Then make a transfer at the same station to take the Metro Line 2 and get off at Jishuitan Station, Exit A. Walk out of the subway and follow the signs to Deshengmen, and you will see the Bus Stop Board No.877 and 911 under the Embrasured Watchtower. You can take the two buses to Badaling Sectionl, which will take about 1.5 to 2 hours and cost CNY12 per person in a single ride.