Considering the influence of phase change and temperature variation on the physical and mechanical properties of low-temperature rock in cold regions, the mathematical model for the Thermo-Hydro(TH) coupled problem is proposed based on the theory of convective heat transfer for porous medium. In this model, the influence of moisture migration on heat conduction in rock is taken into account, as well as the influence of temperature gradient on the seepage. The involved parameters are determined according to the related equations given in this paper. Then the finite element model of a gas transmission pipeline in cold region is established using the proposed mathematical model. By selecting suitable boundary conditions, initial conditions and heat computation parameters, the freezing problem of low-temperature rock surrounding the pipeline is analyzed. The calculated values of the temperature field and the measured data are basically consistent, which indicates that the proposed TH coupling model for rock in cold regions is reasonable and reliable.