The double helix tunnel of Ya’an-Lugu Expressway in Sichuan Province is one of the dominant engineerings of Ya’an-Xichang Expressway in Sichuan Province. It was the first time that in the world’s history of highways, double helix extension was used to overcome the height difference. By widening the clear cross section of the tunnel, the problem of running distance in the tunnel was solved, saving more than 100 million Yuan investment for the project. At the same time, it overcame the key technologies for driving safety on ultra-long consecutive longitudinal sections, the technology for highway tunnels passing through plateau wetlands, the technology for route selection and bridge and tunnel construction in a region of high earthquake intensity, and other worldwide problems, providing a series of groundbreaking new ideas and technologies for the construction of expressways in complex areas.