Following the theory of underground structure design and Drucker-Prager standard for rock yield,the wall rock stability of a highway tunnel in Guangxi was analyzed by finite element method, taking self bearing capacity of wall rock into account. The effects of excavation methods and sequences on wall rock stability were analyzed. The wall rock excavation process was simulated. The displacement, stress condition, and the change pattern of displacement and stress in time were determined, providing the foundation for selection of excavation methods and supporting time in tunnel construction.