Abstract: By using roof dynamic monitoring system, the all-weather, all-round monitoring was carried out for the roof rock activities of fully mechanized caving face, conveying side and return side in Dafosi Coal Mine, the workload of mine pressure monitoring has been greatly reduced, which improves the accuracy, continuity and long-term. Some aspects are obtained timely and accurately in the mining process, including the working conditions of hydraulic support, the periodic pressure step of working face roof, rock activities of roadway roof. In the mining process of working face, roof accidents do not occur, which ensures the rapid push mining in working face.