Abstract: In accordance with the requirements of AQ 6201—2019, the coal mine monitoring system industry standard stipulates that the monitoring system must perform locking within 2 s when the sensor fails or exceeds the limit. At the same time, there are clear provisions on the off-site control and inspection cycle. At present, polling mode is used between sub stations and sensors, sub stations and hosts of the coal mine monitoring system with master-slave communication mode, which has low real-time performance and maximum loss of one patrol cycle, leading to long power off control time in case of sensor failure or overrun, untimely remote control, overtime patrol cycle and other problems. After detailed investigation and analysis on the characteristics of CAN bus, AQ 6201—2019, Technical Scheme for Upgrading Coal Mine Safety Monitoring System（COAJH２０１６］ No. 5）, and combining the application experience of CAN bus in coal mines, this study designs a sensor with hostless communication mode from the aspects of the structure of the hostless monitoring system, CAN bus electromagnetic compatibility, the design of the whole sensor, the key technology of the sensor software, etc. During the continuous operation of the system, there is no abnormal data generated from the sensor, and the methane sensor failure or out of limit power failure test is conducted. The test locking time: the local control locking can be completed within 2 s, and the remote control locking can be completed within 5 s. The technicalindicators meet the AQ 6201—2019 General Technical Requirements for Coal Mine Safety Monitoring System.