In order to study the relationship between joint opening changes of induced joints of concrete arch dam and dam leakage, combined with monitoring data analysis and finite element calculation method, the flow velocity distribution of six induced joints and seepage flow between joints under different openings were simulated. The correlation between joints and dam seepage and the influence of different openings on seepage flow between joints are clarified. The calculation results show that there is a strong correlation between dam leakage and joint opening, and it changes periodically with air temperature. Velocity distribution of induced joints is related to elevation. Compared with induced joints in the middle of riverbed, induced joints in the left and right bank abutments are closer. With the elevation increasing, the velocity between joints also increases gradually, and the seepage velocity near the drainage corridor is larger than that in other areas. With the increase of joint opening, the increasing rate of seepage decreases.