If we stay at Novotel Beijing Xinqiao, which transportation should we (5 of us) take to go to Badaling Great Wall?

Your hotel is close to Chongwenmen Subway Station of Line 2, so you can take the subway line 2 to reach Jishuitan. Then walk to reach Deshengmen Bus Station to take bus 919 to reach Badaling directly.

Thanks for the information, Dave! However, we were still cheated by a group of illegal taxi drivers at Deshengmen Bus Station. They told us that bus no. 919 was no longer going to Badaling Great Wall and had been replaced by bus no. 877. At that time, we arrived at 1.30pm at Deshengmen Bus Station, and the last bus no. 877 left the bus station at 12 noon. Thus, we had no choice and decided to rent a taxi from one of illegal taxi drivers. In fact, they lied by telling us that the return fare was RMB 120 per person (the fact is only RMB 24 per person). Thus, they persuaded us to rent a taxi for RMB 500 for 5 of us, and they convinced us that we had saved RMB 100. For other travelers, who plan to go to Badaling Great Wall, please be careful with this kind of people!