In order to ensure the efficient and safe mining of the 2332 working face of Sanhekou Mine, a temperature - programmed experiment and on-site measurement of the O2 concentration in the goaf along the working surface were used to study the index gas characterizes and the spontaneous combustion of the working face. The range of self-ignition "three belts" showed that the main index gases of natural combustion in No. 3 coal seams were CO and C2H4, the auxiliary prediction index was C2H4 / C2H6，the heat dissipation zone on the inlet side was 0 ~ 70.9 m, and the oxidation zone was 70.9 ~ 151 m, the choking zone>151 m; the return air side heat sink was 0 to 54.5 m, the oxidation zone 54.5 to 121 m, and the asphyxiation zone >121 m. The minimum safe propulsion speed of 2332 working face was calculated to be 1.16 m/d, which provided theoretical guidance for preventing spontaneous combustion of coal in the goaf of 2332 working face.