Abstract: According to deformable coordination condition, the sliding soil mass will deform to adapt to the curve of logarithmic spiral which will lead to energy dissipation. To quantify this energy dissipation, two multi-blocks partitioning methods which are based on the coordinating velocity field are proposed. Combined with the upper bound limit analysis and the strength reduction method, the safety factor of the case of reinforced slopes with prestressed anchor cables is obtained. The calculated results indicate that the influence rules of interface number on the safety factor in the two multi-blocks partitioning methods are different, but both curves converge to a similar value, and the reasons for this are explained from the point of partition principles. The safety factors of typical slopes are calculated and compared with others’ results. It is indicated that the safety factor considering the energy dissipation due to deformation of inner friction is more than the other one, and this energy dissipation contributes to improving the anti-sliding ability of slopes. Moreover, the influences of anchor prestress, anchor inclination and anchor height on the safety factor are respectively analyzed, and in each calculation, two results with and without considering the energy dissipation due to deformation of inner friction are compared. This method makes up for the deficiency of neglecting the energy dissipation due to deformation of inner friction, which can provide references for stability analysis of reinforced slopes with prestressed anchor cables.