Taking Kunlunshan tunnel on QinghaiTibet railway as example, the author analyzes the reasons for the frost heaving of the tunnels in permafrost regions and recommends a new kind of antifrostheaving structure, which is composed of primary reinforcement, waterproofing and thermalinsulating layer and secondary lining. The measurement of the atmospheric temperature and ground temperature at the site of Kunlunshan tunnel and the measurement of the temperature of the surrounding rock mass inside the tunnel, the frostheaving forces and the stresses of the primary reinforcement and the secondary lining show that this kind of lining structure is safe and reliable. The successful construction of Kunlunshan tunnel indicates that the construction technology of permafrost tunnels has achieved great progress.