Abstract: By adapting the idea of limit analysis and finite element analysis an improved slice method for slope stability analysis is proposed. The internal forces on slip surfaces are adjusted through optimiza- tion so that the safety factor is maximized for any given slip surface. The real satety factor should be the minimum one among these possible slip surfaces.This method doesn’t introduce any assumption about the internal forces on slip suriaces,so it can be used to estimate the true stability of slope.