from the beijing international airport to badaling great wall how many km and min. it take , anthank

The distance between the airport and the Wall is around 80km. If you take a taxi to the Wall, it takes around one hour to one hour and a half.
For a cheap and safe method, you need to go to BJ city first and change local public buses to the Wall. You can take the airport express to reach Dongzhimen Station and then change to line 2 to Jishuitan Station. After that you can walk to the Deshengmen Bus Station to take the bus line 919 to reach the Badaling directly.