The best way to get from the capital airport to Tiananmen Square and the Forbidden City

Take Airport Express to Dongzhimen Station. It takes around half an hour. The fare is CNY 25 per person.
Then take subway line 2 to Jianguomen Station and line 1 to Tiananmen East Station, Exit A. The duration is about 15 mins with the fare of CNY 4 per person. After arriving, walk west around 450 yards (410 meters).