Abstract: Aiming at the problem of blasting parameters of the weakening of high in-situ stress weaken hard roof in fully mechanized coal mining face, depending on the project of 3245 working face of Qidong mine, using LS-DYNA to simulate the explosive stress wave in rock mass and the time history curve of blasting vibration when the initial geostress is 20 MPa and the lateral pressure coefficient is 0.5, and studied the peak stress and velocity with the attenuation law of pitch. With the introduction of the initial stress correction coefficient of PPV safety criteria of fracture zone radius, the result shows that when the artillery hole spacing is less than 13.4 m of roof rock blasting damage effect is better, and field application of the rationality of the research conclusion is verified. It provides a reference for the design of similar engineering blasting parameters .