Abstract: Through the construction of Darcy Forchheimer flow coupling analysis numerical model, the evolution laws of porosity, permeability and volume strain in aquifer, fault zone and fracture zone after fault water inrush under fluid-solid coupling were studied, and the mechanism of fault water inrush was revealed.The aquifer, fault fracture zone and fracture zone were grouting, and the evolution mechanism of cross section velocity during the grouting process was obtained.The simulation results show that the Forchheimer equation can effectively simulate the flow process under high water pressure and high velocity.The coupling of pressure and seepage has a significant effect on the non-Darcy flow characteristics in the fault.Through the simulation analysis of different grouting positions, the variation law of the flow velocity during the grouting process is obtained, which is of great significance for selecting the appropriate grouting position and optimizing the grouting technology.