Abstract: In order to use the microseismic monitoring technology to warn the coal mine floor water inrush,based on the mining process of No.22517 working face in Dongjiahe Coal Mine, a microseismic monitoring system adapted to on-site hydrogeological conditions was constructed using microseismic monitoring technology, and the floor of No.22517 working face was monitored.The monitoring results show that the overall trend of No.22517 working face floor tends to be stable, and the microseismic events of the floor are mainly distributed in three areas, namely, the structure affecting microseismic area, the mining affecting microseismic area and the lag microseismic area; most of the microseismic events are concentrated within the range of 12 m, but there are two abnormal areas, and the area Ⅰ has formed floor water channel, and the floor water outlet may be located in the area from 50 m in front of the working face to 30 m in the rear.Through the microseismic monitoring results combined with geological borehole columnar comprehensive analysis to determine the floor damage depth is 11.22 m, the theoretical calculation and the results of the borehole acoustic wave test are 0.32 m and 0.42 m respectively compared with the microseismic monitoring results.