Abstract: The grooving and blasting effect of the drilling and blasting method in roadway tunneling directly affects the blasting cycle efficiency, while the existing studies mostly ignore the influence of mesoscopic defects such as internal joints of rock mass. Based on the PFC 2D discrete element method, a discrete fracture network (DFN) is introduced to construct a rock mass model with different densities of joints, and the particle expansion method is used to simulate the groove blasting process, and the effects of joint density on crack propagation, energy dissipation and post-explosion block size are systematically analyzed. On this basis, the blast hole layout scheme is optimized, the original 6-hole layout is simplified to a 4-hole diamond-shaped layout, and the 15 ms differential detonation is used to improve the explosive energy utilization rate, and the post-detonation effect is similar to the original scheme. Field tests show that the optimization scheme effectively saves the actual production cost and reduces the drilling workload. The research results emphasize the importance of considering the joint defects of rock mass for the optimization of blasting parameters, and provide a theoretical basis and practical reference for efficient tunneling of rock roadways.