Abstract: In order to master the natural oxidation degree in the main coal seam of Qindong coal mine,and relatively forecasting the situation of spontaneous combustion in this coal seam,preventing the happening of coal spontaneous combustion disaster,this article take the CO,C₂H₄,graham and olefins/alkane as the indicator gas systems to analysis the spontaneous combustion oxidizing of the main coal seam of this coal mine,through the natural oxidation heating experiment on the basis of a comprehensive analysis the experimental data.Combination with the characteristics of coal,the paper determined the corresponding relation between each indicator gas and the natural oxidation degree