Hi, it cost about CNY 600 to hire a car for the round trip from Tiananmen Square to Badaling Great Wall, and as far as I know, the taxi drivers would refuse to go because the route is so far. You can take the bus 919 from Deshengmen Gate to Badaling Great Wall. Take bus no.5 from Deshengmen Gate and get off at Deshengmen Gate, take bus no.919 to Badaling Great Wall. The ticket only costs CNY 12.

Hello Mr Jason,
Many thanks for your valuable information. It saves me a lot.