Abstract: In order to solve the problem of roof falling caused by roof breakage and surrounding rock instability during the crossing of faults in fully mechanized mining face, taking the 3-6071 crossheading of Jingfang Coal Mine as the research background, FLAC3D numerical simulation technology is used to simulate the dynamic process of gradual approaching faults in mining face. The distribution characteristics of vertical stress field, the expansion law of plastic failure area and the amount of tectonic slip displacement in different advancing stages are analyzed, and the control technology system of safe crossing fault zone is formed. The results show that when the distance between the fully mechanized mining face and the fault is 35 m, the stress value near the fault zone is 25 MPa, and the plastic damage area has run through the direct floor. The plastic damage range of the roof and floor of the working face is significantly expanded, and the structural integrity of the surrounding rock is deteriorated. As the mining activities continue to extend to the fault zone, the fault structure eventually presents an overall instability state. Based on this, it is established that the Marithan grouting reinforcement process is started when the mining face is 35 m away from the fault, and the cement-based material composite grouting technology is implemented in the No.25-55 hydraulic support interval. The engineering verification shows that this measure can effectively maintain the stable state of the support pressure system.