Abstract: In this paper the slices method for sliding stabil ity calculation of e arth slope is analyzed and its existing problems are indicated. At the same time the f inite element method for circular slip surface is proposed,for which the pore w ater pressure acting around each vertical slice is replaced by seepage force of triangular element. So the seepage direction with its effect of moment has been considered correctly .Not only the accuracy but also the convenience in calculation is increased due to that the stability calculation i s sequentially carried out after seepage calculation in one computer program.