For the high-speed railway tunnel in cold regions, the frost heave of the surrounding rock behind the lining causes the tunnel disease. Taking the Yushuchuan tunnel on the Jituhui passenger dedicated line as an example, a numerical heat-moisture coupled model considering heat conduction, water migration and phase transition for the tunnel in cold regions is established. Meantime, the temperature field of the Yushuchuan tunnel is calculated. Then, the unfavorable freezing position and the unfavorable freezing time are determined, and the relationship between the maximum freezing depth at the unfavorable freezing position and the mean annual temperature is established, which provides a basis for determining the freezing depth at different depths in the tunnel. Afterwards, the thermal insulation effect of thermal insulation layer on thermal state is analyzed. In addition, the optimum thickness and thermal conductivity of the thermal insulation layer are suggested to prevent the tunnel from freezing. This study will provide a theoretical reference for the insulation layer design of the tunnel in cold regions.