Abstract In the paper, an improved contact element method was adopted to analyze the sliding process of slopes. The normal and shear strengths of materials on potential sliding surfaces of slopes were considered. The convergence of nonlinear problems on frictional contact boundaries was reached through a repeated contact calculation. A step-by-step procedure was used to simulate the process of landslides. The energy change of the slope system at each step was calculated, considering the strain energy, kinetic energy and the work of friction force, etc. In the simulation of rock slopes, it was found that there were three main states: a ‘perfectly bounded’ state, a ‘local sliding’ state and a ‘whole sliding’ state. The effects of weathering and water infiltrating into the sliding surfaces were considered, and the displacements of landslides were obtained. For a real case history, application of the code to results of an actual landslide is given. The simulation method described here may be employed to predict other kinds of landslides because it is not restricted to particular slopes, material properties of slopes or shapes of potential sliding surfaces.