[Objective] To establish a reliable groundwater numerical model, and to provide reference for the prediction of coal mine pit water inflow.[Methods] The flow process conduit(CFP) of Modflow-2005 was used to simulate the dewatering test of a coal mine, and the uncertainty analysis of hydrogeological parameters was carried out using local sensitivity analysis method.[Results] A coupling model of seepage and pipe flow was established. After repeated adjustment and analysis of fitting results, the best fitting of the hydrogeological parameters was obtained. Through sensitivity analysis, the maximum sensitivity parameter was obtained.[Conclusion] There are big differences in the permeability of the aquifers in the study area, precautions should be taken in the process of drainage. The sensitivity analysis results showed that the conductance of the pipe has the greatest influence. Vertically, of Lower Jurassic Yan'an group(J₂Y)the permeability was higher than that of other aquifer groups.