After the excavation of abutment slope, the stress redistributed and the rock mass quality degradation damaged. According to fore-and-aft change of stresses for excavation, the authors divided excavation area and chose suitable mechanical parameters of rock mass for different excavation area. We used theory and methods of unloading rock mass mechanics and used elastic-plastic viscous damage mechanics model to give 2-D finite element analysis of stress and strain for typical profiles. And then we analyzed the changes of stress and deformation of the slope at nature and unloading conditions, analyzed deformation and stability at different reinforcement areas of the slope to choose reasonable reinforcement area. Strengthening plans of rock mass are analyzed and compared to choose reasonable reinforcement plan. The research results herein can offer beneficial reference for the design and the construction engineers.