Abstract: In this paper, a method of controlling mine earthquake by weakening the key layer of low position is given.Dongtan coal mine 63upper03 working face is taken as the engineering background. By using the methods of field investigation, theoretical analysis and field test, the principle of mine earthquake prevention and control technology is analyzed, the position of key layer is determined, and the hydraulic fracturing weakening test is carried out for key layer. Geological analysis and theoretical calculation show that the main key layer is fine sandstone 226.72 m away from the roof, and the sub key layer is fine sandstone and medium sandstone 163.92 m and 15.13 m away from the roof. In the sub key layer, the sandstone layer is weakened by directional long hole staged hydraulic fracturing. After fracturing treatment, the daily average number of mine seismic events with energy greater than 5 × 103J decreased by 95.45%. This technology makes the high energy gathered in the key layer disperse and release.