Abstract: For the excavation of rock mass under high stress, the defects of the rock mass and the dynamic effects induced by the excavation have a great impact on the damage of the surrounding rock. The distribution of joints is simplified and quantified. Based on the two-dimensional discrete element method, the process of excavation of rock masses with non-persistent joints is simulated. The macro-and micro-dynamic failure modes of the rock mass under different connectivity rates and the dynamic response near the joint are studied. The results show that after considering the dynamic effect, the range and degree of damage increase significantly. The dynamic model is more likely to produce wing crack coalescence under high connectivity. The joint amplifies the dynamic effect at the rock bridge center and acts as a cushion to absorb the shock behind the joint, but the rock mass before the joint will be affected by the reflected stress waves.