Soil slope is one of the main parts of the road engineering. The stability of the slope is an essential prerequisite to ensure the safe operation of road transport. In seasonal frozen regions, shallow landslide hazards in soil slopes usually happen, which pose a serious threat to road safety operations. During the melting process, there forms stagnant water lubrication between the melting soil and freezing soil interface, which constitutes the weak interface of landslide hazard. Special methods to form the freezing – thawing (F-T) surface is designed, and takes consider the interface strength as the foundation of experimental tests, then opening to research the soil slope stability. Safety factor modification of the soil slope is presented. The conclusions of this paper present well theoretical and applied value to the regional slope failure analysis.