Abstract: In order to explore the mechanical response characteristics of faults when the working face is normal fault mining, a numerical simulation model is established based on the engineering geological conditions of 1105 working face in Gaozhuang Coal Mine to obtain the evolution characteristics of fault damage variables under mining disturbance. The simulation results are analyzed by multiple linear regression analysis and the mechanical model of footwall rock mass is established to obtain the relationship between fault damage variables and coal stress. The results show that the fracture damage of the fault develops from the high rock layer to the low rock layer. When the fault damage variable reaches the critical value, the fault has the condition to activate; under the influence of working face mining, the development of fault damage variable is earlier than the increase of abutment pressure of coal body. Fault damage variable can be used as a key index to predict fault activation and coal body stress increase; through multiple linear regression analysis, the determined influencing factors of fault damage variables are distance from fault, vertical stress, internal friction angle of fault and fault cohesion; in the process of working face to fault mining, the decrease of coal width between working face and fault causes the increase of coal stress. At the same time, the mining leads to the damage development of the fault surface, the effective bearing area between the upper and lower rock mass is reduced, the weight of the rock mass is mostly borne by the lower coal body, and the coal body stress is further increased.