Abstract: For the problems that there are much more disasters in coal mine roof and the artificial monitoring roof are not in time,the paper designs a kind of roof dynamic on-line monitoring system in coal mine and introduces the technical principle and basic structure,function module and the application efficiency of the monitoring system in detail.Practical application shows that the system realize the fusion and visualized analysis among roof pressure,displacement,stress monitoring data,which can provide rapid and accurate early warning and forecast for coal mine safety hidden trouble on roof.