What is the best way to take from Beijing to Datong ? How long it takes ? and How much is it ?

You may use train or plane to travel between.

By train, it takes 6h or longer and costs CNY47.5-53.5 for a hard seat, CNY99.5-107.5 for a hard sleeper and CNY146.5-158.5 for a soft sleeper.

By plane, take a flight at Nanyuan Airport to get to Datong within 40min. As there are discount for air tickets, the lowest fare shall be CNY150 or around. The fare may vary from time to time.

Generally, for a good visit, it is suggested to stay in Datong for 2-3 days.