The hazardous gas monitoring system mainly includes two parts: system host and monitor. The system collects the corresponding gas roll through the monitor, converts the concentration of the target gas into electrical signals, and finally calculates the concentration of the gas to be monitored after filtering, amplification and AD analog-to-digital conversion by the acquisition and processing circuit, and displays the calculation results on the monitor's display screen. At the same time, it transmits the data to the system host through wireless network for display and processing.