Abstract: The source of water filling mainly originates from the pressurized aquifer in mining deep coal seams, which seriously affects the safety of coal mine. Taking the north wing of Fangezhuang Coal Mine as an example, the geological “skylight” was delineated according to the 5^# coal seam gob and hydro-geological conditions, and the groundwater flow field model in the study area was established by using the GMS (Groundwater Modeling System) numerical simulation software; the model was identified based on the first stage water discharge experimental data, and the second stage water discharge experimental data was used to verify the model, and the geological “skylights” in the study area were processed using parameter zoning; the water inflow in the mining process of 12^# coal 2022 working face and the groundwater flow field of sandstone fissure confined aquifer between 5^# and 12^# coal seams are predicted by model. The results show that with the mining of the working face, the water inflow of the working face increases gradually, the drop funnel centered on the goaf expands gradually, and finally affects the geological “skylight” of the water-resisting layer of the top and bottom of the fifth coal seam.