Xishan tunnel on TaiyuanGujiao highway in Shanxi province is a superlong road tunnel with about 13.68km×2 length. It is so far the second longest highway tunnel in China. In the investigation and design phases, the successful experience in highway tunnel construction both in China and abroad was fully adopted and many experts were invited to hold consultation and argumentation. The article briefly introduces the project, the geological conditions,  civil engineering design, accessorial works design of the tunnel and the research activities on some key techniques.