Abstract: Baihetan hydropower station with an installed capacity more than 10,000MW is the third largest hydropower station in China after the Three Gorges project and Xiluodu project. At its dam site have developed columnar jointed rocks that are anisotropic materials with lower mechanical strengths. To reduce the negative influence of these rocks and faults a reinforcement scheme was proposed for stability and security of the dam. Based on the geological data, an accurate three-dimensional numerical model was developed, and a transversely isotropic elastic-plastic constitutive model was adopted for describing the mechanical behaviors of columnar jointed rocks. This paper discusses the influence of anistropy using the simulations by the transversely isotropic constitutive model and the isotropic constitutive model, and presents a comparative analysis on deformation and stress distributions in the dam and foundation in the schemes of reinforcement and no reinforcement. And the overall stability of dam-foundation is evaluated by using water pressure overload method. This study provides a technical support to the final-stage feasibility study on Baihetan hydropower station.