Abstract: The improved limit equilibrium method, which bases on the finite element stress field to analyze the stability of a slope, has an advantage in the analysis of the stability of a slope or a foundation with complex geological composition and strong coupling effect of seepage and effective stresses. In this paper, a virtual power method for slope stability analysis is proposed. The safety factor is calculated by using the ratio of anti-slip power to sliding power on the velocity discontinuities of the sliding mechanism by using the permissible velocity field for maneuvering of the combined rigid body sliding mechanism and the finite element stress field. The stability safety factor of a given sliding mechanism of the slope is obtained by the method of a step by step optimization strategy. Two typical sliding slope cases with weak interlayers are analyzed, including the comparison of the influence to the safety factor results of the stress fields whether static equilibrium only or also hydrostatic allowable. The safety factor in virtual power safety factor method based on linear elastic effective stress field is still a good measure to the stability of a slope even if it is not the best while the stress field is not static permissible. Slope safety factors calculated here are very close to the reference answers in the literature, the sliding mechanisms are consistent with and the safety coefficients are close to that of by the strength reduction finite element method. These show that the proposed method is reasonable. The proposed method is an alternative for the stability analysis of slopes and foundations.