Abstract: Based on the problem of high risk of impact caused by large drop fault, irregular triangular coal pillar, isolated island and thick and hard roof in 3 upper 215 working face of a mine, the deformation and failure, stress distribution and energy evolution characteristics in the mining process of working face are analyzed by combining theoretical analysis, numerical simulation and field application. The results show that when the width of irregular coal pillar is about 10 m, the peak value of vertical stress concentration coefficient in the residual coal pillar area under the influence of goaf and fault 1 is increased by 69 % compared with that in the non-coal pillar area, and the plastic zone of coal pillar is connected with the plastic zone of goaf. During the period of mining to the first square, the superposition of the advanced abutment pressure and the lateral abutment pressure of the goaf reaches 59.93 MPa, and the stress concentration factor reaches 3.55. Irregular residual coal pillars and two faults also showed the accumulation of elastic energy. The comparative analysis of the simulation data before and after the implementation of pressure relief shows that the stress of the working face is greatly reduced, and the accumulated elastic energy is released, which proves the feasibility of the pressure relief scheme. After the implementation of roof breaking and coal seam pressure relief in the engineering site, the impact danger of the composite affected area is effectively reduced, and the safe mining is realized.