Take Metro Line 9 first, and then take Metro Line 4 Daxing Line. According to Baidu map, the distance from Jingxi to the old campus of Tsinghua is12.8km. You need to take Metro Line 9 first and then Daxing Line of Metro Line 4 to get there. The specific steps are as follows:

1. First walk from Beijing West Railway Station 10 meters, and then get on the bus at Beijing West Railway Station.

Secondly, take Metro Line 9, get off at National Library Station, and then transfer to Daxing Line of Metro Line 4.

3. Finally, get off at Yuanmingyuan Station (northeast of Exit B) and walk 620 meters to the old campus of Tsinghua University.