According to the characteristics of coal seam mining, an intelligent monitoring system of coal mine abscission is designed. The intelligent monitoring device includes micro laser ranging module, an integrated protective fixture, wireless transmission module, DC module, base station and upper computer software. In this paper, the structure of the system and the arrangement of measuring points are presented, the hardware and software design of the system used to accurately measure the displacement of roof abscission layer is introduced in detail, and the alarm threshold of roof abscission layer displacement is analyzed. The test results show that the system can monitor the displacement of the roof separation layer in real time.