Abstract: Permeable faults in the well field can lead to intermittent production or groundwater protrusion problems in the underlying aquifer. In order to determine the groundwater transport law near the downhole faults, the groundwater protrusion in the fault zone of the coal mine was numerically investigated by using the numerical calculation program of RFPA based on the finite element method. The damage evolution law obtained from the numerical simulation shows that the basement rock layer can be divided into three zones: mining fissure zone, intact zone and fault activation zone, among which the intact zone is the key part to resist groundwater protrusion, which directly determines the effective thickness of the water-insulating rock layer. The geometry of faults also has an important influence on groundwater protrusion. Finally, based on the results of geological and hydrogeological investigations and numerical calculations, the mechanism of groundwater protrusion is analyzed in the project example, which is of great significance in guiding the research on the mechanism of fault-induced groundwater protrusion and the prevention and control practice.