The Finite Elements Method (FEM) is implored to simulate excavation of slope. The deformation of the excavated slope is computed. The factor of safety of the slope is solved by using shear strength re- duction technique and the critical slip surface can be easily obtained through the max shear strain contours of the slope at failure. The FEM results are able to evaluate the slope stability and the dangerous zone of the excavated slope can be obtained, which is valuable for slope excavation.