Located at the junction of Luding, Tianquan and Yingjing three counties, at an altitude of 3,437 meters, Jiajin Mountain to the north, Lushan to the south, and Gongga Mountain to the west echoed, once a "one husband is a gateway, a millionfu is not open" on the Sichuan-Tibet line. The Erlang Mountain Tunnel, which has been built at an altitude of 2182 meters, is 8,660 meters long. It is the longest road tunnel in Asia and the longest and highest altitude of the road tunnel that has been connected in China. The completion of the Erlang Mountain Tunnel shortened the mileage of the Erlang Mountain section of the original Sichuan-Tibet Highway by 25 kilometers, reduced the driving time by 3 hours, and avoided the section of the mountaintop accidents and disasters, ensuring the smooth road and safety of driving. Every May, Erlang Mountain is full of purple, blue, red and white rhododendrons, especially beautiful against the solemn and quiet ancient glaciers. The ramp flies over Erlang Mountain and Kangding City on the Dadu River.