Based on vertical one-dimensional water and heat movement in soil under seasonal freezing and thawing, a water-heat coupling model was used to simulate variation of moisture and temperature in soil with surface energy and mass in balance. The simulation took into account the effect of ice and water, at times of freezing, on volumetric heat capacity, heat conduction and hydraulic conductivity and the effect of snow cover on the soil surface as well. The model used the meteorological data collected at the weather stations in the studied area during the three years from Jan. 1, 2008 to Dec. 13, 2010 and was verified with observed data of soil temperature, soil moisture, and depth of freezing. Results show that the simulated and the measured data of soil temperature varied with a root mean square error of 3.65, 1.59, 1.75, 1.35 and 1.64℃ at 0, 0.05, 0.40, 0.80 and 1.60m in depth, respectively. The data of frozen depth was almost identical. And the data of soil moisture differed with a mean error of 3% at all the depths except for the surface, and with a root mean square error (RMSE) of less than 4%. Therefore, it could be concluded that the model presented in this study could be used to simulate water and heat movement within a certain depth of soil under seasonal freezing and thawing. It can also be used to study laws of the variation of soil water-heat in the active layer in the permanent frosted regions. Coupled with the ecological process model it will help improve precision of the frozen soil eco-environment model in simulating soil temperature, soil moisture and depth of freezing.