Abstract: The minimum potential energy method is an analysis method used to figure out the stability coefficient of slopes,whose core is to determine the potential energy model and the sliding direction.In this paper,the elastic energy on sliding plane was determined by introducing the elastic foundation beam model,and the shear potential energy calculation model was established based on the whole equilibrium equation of the sliding mass on the virtual displacement direction.After determining the boundary condition of the slope,the virtual displacement could be confirmed according to the principle of minimum potential energy,and by defining different sliding directions,different stability coefficients could be obtained.Three formulas were given out to determine the whole sliding direction of sliding mass.At last,we applied the proposed method to discuss the sliding direction and stability coefficient of engineering cases of fixed sliding surface and the non-fixed sliding surface.The results showed that using the vector synthesis of the sliding directions of different sliding points on the sliding surface as the whole sliding direction had good physical meanings,and the result was reasonable too.