How to get from the Beijing Airport to Wudaokou after midnight by bus?

Well, you can take airport shuttle bus line 2 Night Line to the terminus and then change to a taxi to your destination at the expense of CNY30 or so. The night line operates till the arrival of the last domestic flight, which I heard arrives around 1:00am. Hope you can catch it. If not, ride a taxi for a direct travel and the cost shall be around CNY120.