Abstract: In view of the hard and hard roof that is difficult to collapse in the mining process of extra thick coal seams, the super long drilling hydraulic fracturing technology is adopted to fracture the hard rock above the coal seams, effectively reducing the overall strength of the overlying rock roof, cutting the thick and complete roof through high-pressure water, and finally achieving the purpose of weakening the large-area roof.The results show that the implementation of the hydraulic fracturing project of super long drilling hole in the roof has cut and weakened the gravelly coarse sandstone at 55-59 m above the coal seam of 40205 working face and the gravelly coarse sandstone at 68 m above the coal seam, effectively reducing the impact potential energy of the hard roof above the coal seam.According to the analysis of the joint monitoring data of ARAMIS M/E microseismic monitoring and ARES-5/E geophonic monitoring, during the roof hydraulic fracturing process, the energy event mainly exists in the state of "high frequency and low energy", with the highest energy event reaching 6 200 J, and there is no high energy accumulation and roof fracture phenomenon.After the high-pressure hydraulic fracturing construction, during the mining period of the working face, the total energy per day decreased by 71.7%, and the internal fractures of the rock mass presented a "grid" distribution structure.The implementation of the hydraulic fracturing technology of ultra long borehole effectively reduces the impact potential energy of the roof above the coal seam in the mining process of the working face, and provides a safety guarantee for the mining of the working face.