Abstract: The stability evaluation of a rock mass slope with regular weak intercalated layers is discussed. On the basis ofthe plasticity limit analysis, the energy coefficient is proposed to evaluate the stabilityof rock mass slopes using the movable mechanismmethod, with a set of formula derived. The stability of an actual landslide located at the Sichuan-Tibet highway is analyzed using the method proposed in this paper and the traditional limit equilibrium method, respectively. By comparing the results, the evaluation method suggested proves feasible.