According to the numerical model of moisture-heat-stress coupled field, the finite element algorithm for soilbags was built, and then one canal engineering project in the cold area has been analyzed to obtain the distributions of temperature field, moisture field and displacement within two years after the completion of project. The results show that the canal slope encounters significant frost heaving and melting deformation during the freezing and thawing process, and both the frost heaving and the melting deformation are irreversible. The geotextile treated channel has a good performance in preventing frost heaving of frozen soil slope. It also has the advantage of small thermal conductivity that can effectively reduce the influence of atmosphere temperature on the soil temperature inside canal slope, so as to reduce the possibility of frost heaving and melting settlement. At the same time, soilbags can suppress the rise of capillary water and film water and reduce the water immigration of the geotextile bag layer and the lower part, so as to maintain a more stable water content within the channel to reduce the frost heaving of canal surface. In addition, the geotextile bag has a certain strength, and under the action of its tension stress, the frost heaving can be suppressed, thereby reducing the damage of frost heaving on the channel lining. At last, with the treated surface of channel using the geotextile bag, the internal temperature of slope can quickly reach a steady state, and after 2 years, a more stable and perennial frozen layer is formed below 2 m of the ground.