The exploitation of coal mines has brought great benefits to the development of the national economy, but it has also caused many environmental geological problems, especially in the process of coal seam mining, where the fracture channel formed by deformation and failure of the overlying bedrock in coal seams is prone to mine gushing (figure) water accidents, threatening the lives of underground workers at any time. In this paper, taking the 051505 working face of Lingxin Mine as the research object, the height of the water flowing fractured zone in the overlying bedrock in the No.14 main mining coal seam is simulated by using the Flac3D numerical simulation software. The simulation results show that when the mining thickness of the coal seam is 2.5m, the maximum height of the water flowing fractured zone is 59.5m. At the same time, the empirical formula method is selected to calculate the height of the water flowing fractured zone. Finally, the results obtained by borehole measurements are compared with the first two methods. The numerical simulation results are in good agreement with the measured borehole results. It is concluded that the numerical simulation method can achieve the purpose of predicting the height of the water flowing fractured zone efficiently, simply and reasonably. It also provides some reference for the safety and green production of the similar mines.