Abstract: To solve the problems such as low communication efficiency and susceptibility to interference caused by the RS485 bus communication between the substation and sensors of monitoring system for coal mine safety through the mode of call and answer, the communication method of irregularly controlled RS485 bus is designed. The substation sends the control frame of bus device address information to actively interfere with the bus. The sensors compare their communication address with the bus device address information and determine the order of uploading data, so as to actively send data to the bus. Therefore, the acquisition efficiency of the sensor measurement data of the substation is improved, and the system response time is shortened. Laboratory tests and field industrial experiments show that this communication method can ensure fast and stable RS485 bus communication.