Abstract: In order to control the disasters of rock burst and improve the efficiency of pressure relief, based on the key stratum theory, we establish mechanics analysis model for fault activation at reverse fault upper wall mining face, reveal the mechanism of fault activation and obtain mechanical expression of fault activation range. The calculation results showed that with the increasing of mining height and fault angle, the range of fault activation increased; the less friction coefficient of fault was, the larger rarge of fault activation was. Combined with the actual geological conditions of Qiandu Mine, the fault began to activate when the working face advanced to the location away from the fault 33.36 m; large-diameter bore, seam water injection, coal blasting were used to relieve the pressure and ensure the safety of coal mining through fault, and the efficiency of controlling disasters of rock burst was increased.