IHEP is located in the west of Beijing.
There are two international airports in Beijing, Beijing Capital International Airport (PEK) and Beijing Nanyuan Airport (NAY). Most flights are through Beijing Capital International Airport.
Directions from Beijing Capital International Airport to IHEP:
1) By taxi:
You can get a taxi right outside the arrival terminals. It is about 40 km from the airport to IHEP. The fare should be about 150 RMB (about 20 EUR) depending on time of day and traffic conditions.
2) By subway:
You can take Beijing Subway Airport Express from Airport Terminals 2 and 3 to Dongzhimen Station, from which you should transfer to Line 2. Change from Line 2 to Line 1 at Jianguomen Station, taking the train in the Pingguoyuan direction, and get off at Yuquanlu Station, exiting by the north-west exit (A). The IHEP campus is just at the north-west corner of the crossroads; you can enter by the south gate (300 m west of Subway exit A). Note that the subway may be extremely crowded at peak times and that you will have to negotiate long flights of stairs, so it is unsuitable if you have heavy baggage or mobility problems.
3) By Airport shuttle bus:
There are numerous airport shuttle buses to different parts of the city. The closest to IHEP is route 16 towards Shijingshan, getting off at Lugu (third last stop). From there, you can take a taxi to IHEP for about 13 RMB (about 2 EUR). You can also take bus route 4 to Gongzhufen, getting off at the last stop. From there you can take a taxi to IHEP for about 25 RMB (4 EUR). The bus fare is about 24 RMB (4 EUR).