Abstract: Faults are prone to be activated under the influence of mining, often causing accidents such as landslides, roof collapse, water inrush, mine earthquake, rock burst and others. In order to find out the conditions for the activation of the fault, the fault zone, the upper plate and the lower plate were regarded as a system. The stability of fault under the influence of mining and the influence of system parameters on the stability of fault were studied through theoretical analysis, and Anderson fault model and Mohr-Coulomb strength criterion were used. The results show that the fault is in self-locking or activation state, depending on the relationship between the apparent friction coefficient k1 and the fault friction factor k; the fault is in self-locking state when k1