The line traces the Ming dynasty inner city wall, which was demolished and paved over by the 2nd Ring Road and Qianmen Avenue to make room.

[4] Line 2 encircles the old city center districts of Dongcheng and Xicheng and skirts the western edge of Chaoyang.

[citation needed] Eleven of Line 2's eighteen stations are named after gates in the old city wall.

The line was a 16.1 km (10.0 mi) long upside down "horseshoe" along the west, north and east 2nd Ring Road, with 12 stations.

The completed line was called the "Beijing Subway Loop" and is 23 km (14 mi) long with 18 stations.