Abstract: To deal with the complicated environmental conditions of the coal mine, in order to improve the flexibility, accuracy and timeliness of information interaction between coal mine safety monitoring system and equipment, in this paper, a monitoring sub-station based on CAN bus multi-master communication technology is designed. Firstly, the hardware circuit of the monitoring sub-station is designed as a whole, and then the communication protocol of CAN bus is optimized. The optimized protocol can realize multi-master communication of monitoring sub-station through reasonable design of address domain and address arrangement. Multi-master communication monitoring sub-station can effectively support bus multi-master communication, and the communication efficiency and flexibility of the system have been greatly improved.