Abstract: Coal mine water disaster is one of the main disasters in coal mines, with highly destructive.It not only prone to causing property damage to enterprises, but also leads to heavy casualties, and it is difficult to carry out emergency rescue and resume production. The water channel is one of the three elements of coal mine water disaster. The failure of coal mine floor can generate cracks and also trigger microseismic events. Therefore, microseismic monitoring technology can monitor the depth failure of the working face floor. Due to factors such as non-uniform rock layers, undulations in the floor, and hidden structures, the depth of floor failure is not uniform. In this paper, the well ground hole microseismic monitoring technology is used to monitor the mining damage of the 11916 working face floor in Gequan Mine. A three-dimensional geological model of the working face floor is established based on data such as floor contours, tunnel exposure, and floor grouting holes. Subsequently, the floor rock stratum was divided into several grids and the microseismic energy density of each grid was calculated, thereby obtaining the isosurface of microseismic energy density and deducing the floor failure surface. The segmented water pressure test was used to detect the depth of the floor failure in different areas. The results showed that the floor failure surface and its change trend using this method were highly consistent with the water pressure test results, confirming the feasibility and availability of this method.