In order to improve the safety of coal mine production further, the paper designs a roof abscission layer wireless monitoring system based on 433MHz RF technology. Monitoring sub-stations and nodes under the ground form a distributed wireless network and communicate with each other via wireless data transmission module CC1100. In this wireless network, sub-stations, connecting to remote monitoring center via underground fiber optic ring network, are the network gateway, which are responsible for managing nodes near the sub-station and collecting monitoring data. Nodes, using the displacement sensor to monitor the roof separation displacement information, adopt MSP430 chip as the microprocessor and have the characteristic of low power, auto sleep function and several ways to wake up. The system we designed is benefit for using radio frequency technology to communicate under the mine. It can not only monitor the roof separation displacement information real-time and send the warning message timely, but also reduce the cost of installation and maintenance.