During the mining process of working face, the rock integrity of the side floor of the goaf is damaged under the stress, and the fractures are developed. However, how deep the fractures are, whether they can lead through the deep Ordovician limestone aquifer is still blank in domestic research. In order to ensure the safety of mining face, the technology of preventing water inrush in mining face in advance was adopted, such as establishing micro-seismic monitoring system, reserving hydrological observation hole on the floor, and using mine hydrological automatic monitoring system to monitor the development of fractures. The results showed that the technology of over-prevention of water breakout at the workings can play an early warning role, avoiding the occurrence of water breakout and flooding accidents and ensuring the safe recovery of the working face.