Abstract: Two-hole blasting of jointed rock mass under different in-situ stress conditions(lateral pressure coefficient:0.5,1 and 2; vertical stress:5 MPa and 10 MPa) and joint angles(30°,45°,60° and 90°) was numerically simulated to study the process of crack initiation,propagation and coalescence. In the simulation,rock damage was induced by stress waves and explosion gas pressure. Simulation results indicate that for rock without a joint,the initial stress field has a guide role on crack propagation,and the crack propagation direction coincides with the maximum compressive principal stress. However,the existing joint has effect on the crack propagation direction. When the joint angle is 30°,the blasting induced crack connects with the joint and forms a "z" shape.The existing joint would play a positive role in promoting crack initiation and propagation and favor crack propagation along the vertical direction.