The temperature field variation rules and thermal retardation parameters of Zhongtianshan tunnel on TurpanKorla railway located in seasonal frozen area are studied, so as to avoid damages caused by insufficient thermal retardation countermeasures. Prediction and comparison and contrast are made on the freezingthawing cycle ring of tunnels with and without thermal retardation layers, by means of ANSYS FE software and on basis of field tests on the temperature field of the rock mass, with such influence factors as the hydrogeology conditions, the hydration heat of the concrete lining, the atmospheric temperature and the ground temperature being considered. It is concluded that it is necessary to install thermal retardation side ditches, as well as thermal retardation layers with their thickness being more than 5cm and their thermal conductivity being smaller than 0.03 W/(m•K).