Huainan Mining Group uses the coal mine gas passive monitoring emergency system provided by Hanhai Opto-electronic to set up detection points for west air shafts and working faces for online gas monitoring. The underground monitoring equipment of the system can work without connecting to any movie, so as to avoid the problem of underground power failure and unable to provide gas monitoring data. At the same time, it provides the only effective method for gas monitoring in areas without power supply such as goafs. The system does not need to be calibrated during the entire use period, which greatly reduces the manpower and material resources required for maintenance work, and greatly reduces the production cost. It can fully meet the needs of underground gas monitoring and emergency monitoring. It is an upgrade of coal mine gas monitoring equipment.