Based on the problems of the surrounding rock changes, the difficulty of monitoring and poor early warning ability in mining, especially 50 meters before working face, a kind of online monitoring early warning system was set up and details structure of the system, principle, data transmission mode, functional module and early warning method were introduced. The practical application showed that the system achieved the visualization monitoring and data analysis of roof separation, stress and acoustic emission, and the multi-parameter comprehensive early warning can improve the accuracy of the result.