The entry of high-pressure fracturing fluid into the formation during multistage fracturing causes changes in the stress state of the formation near the wellbore, which can easily lead to faults slip around the well. In order to investigate the influence of the design parameters of fracturing section on the probability of fault slip during multistage fracturing, this paper establishes different three-dimensional numerical models to get the pore pressure around the well by presetting the fracture and changing the hydraulic fracture length, fracturing cluster spacing and interval. Then, based on the effect of pore pressure on ground stress, the calculation model of fault slip probability considering the change of pore pressure is derived. Combining the simulation results with the mathematical model, the influence laws of different fracturing segment design parameters on the pore pressure and fault slip probability around the well are analyzed. The research results show that: (1) the longer the hydraulic fracture, the larger the range of high pore pressure zone formed during fracturing, and the probability of fault slip increases; (2) the spacing of fracturing clusters increases, the range of high pore pressure zone formed increases, the pressure between clusters decreases, the pressure between adjacent fracture segments increases, and the probability of slip increases; and (3) the spacing of fracturing segments increases, the range of high pore pressure zone formed increases, the inter-segment connectivity becomes worse, the pressure between adjacent fracture segments decreases, and the probability of slip decreases.