Abstract: In order to study the evolution law and distribution range of the “three zones” of coal spontaneous combustion in goaf, the 1402 fully mechanized mining face of Donggou Coal Mine was taken as the research object.The indicator gas types of coal seam spontaneous combustion were determined through programmed temperature experiments, and the “three zones” of spontaneous combustion before and after nitrogen injection in the goaf of 1402 fully mechanized mining face were determined through numerical simulation and on-site observation.The results show that CO,C₂H₄,and C₂H₄/C₃H₈ can be used as indicator gases for spontaneous combustion in Kuangou Coal Mine.The range of the “three zones” of spontaneous combustion after nitrogen injection is determined as follows: the inlet side belongs to the heat dissipation zone in the goaf area 15.4 m away from the working face, and the return side belongs to the heat dissipation zone 18.6 m away from the working face.The intake side belongs to the oxidation zone within the goaf area 15.4～53.6 m away from the working face, and the return side belongs to the oxidation zone 18.6～66.4 m away from the working face; After the intake side of the goaf reaches 53.6 m and the return side reaches 66.4 m, it enters the suffocation zone, compared to the range of the “three zones” of spontaneous combustion before nitrogen injection.Nitrogen injection significantly reduces the width and area of the oxidation zone, resulting in a 21.8 m reduction in the width of the oxidation zone on the inlet side compared to before nitrogen injection, effectively reducing the difficulty of controlling the risk of spontaneous combustion in goaf.