The Coal Spontaneous Combustion Underground Monitoring System of Duketech is used to monitor the gas content of O2, N2, H2, He,CO, CO2, CH4, C2H4, C2H6, C2H2,H2S,SO2,temperature, pressure, and so on. The regularity of formation of multi-component index gases during spontaneous combustion of coal is detected, which provides technical support and theoretical support for the identification of early hidden danger characteristic information of spontaneous combustion of coal.The system analysis host is based on infrared spectroscopy technology, has pulse infrared light source, and forms 10 spectral bands in mid-infrared region through narrow-band optical filter for gas analysis; ultra-high sensitivity patented optical technology with enhanced beam can be realized through 10 narrow-band optical filters, and ultra-narrow optical filter can remove the interference of background gas; Multi-spectral region can help to minimize the cross sensitivity. It can measure up to 9 kinds of gases at the same time. Multi-point sampler can freely expand gas sampling points from 12 channels to 64 channels. The instrument can be applied to small flow gas sampling and high temperature gas working conditions. Configuration and control are carried out by the application software on Win-PC, and data are automatically stored in Excel format. Standard digital or analog output is realized through different interfaces. At the same time of 64 channels of simultaneous sampling, 64 channels of temperature sensor and pressure sensor can be connected to the multi-point sampling unit to measure the sampling gas temperature, air temperature, surface temperature, working temperature and pressure of the multi-point sampling unit.