In this paper, the spontaneous combustion coal seam No.5 in the Yinhe well area of Huoshaopu Coal Mine of Guizhou Panzhou Yinhe Mining Co., Ltd.was taken as the research object. Through the temperature programmed oxidation experiment and gas chromatography analysis, the formation rules of CO, olefins, alkanes and other gases and their key temperature thresholds during the oxidation and heating process of coal samples were systematically studied. The experimental results show that CO begins to precipitate at 82 ℃, its concentration increases significantly after 118 ℃, and increases exponentially with temperature before 251℃, which can be used as an early warning index for the slow oxidation stage. The critical temperature of C2H4 is 164 ℃, and its concentration reaches the peak at about 251 ℃, which indicates that the coal enters the accelerated oxidation stage. C2H2 begins to form at 286 ℃, which is the characteristic gas of coal entering the stage of intense oxidation combustion. In addition, the study proposes that C2H4/C2H6 and C3H8/C2H6 can be used as auxiliary discriminant indicators, while C2H6, which is greatly affected by adsorption and mining, and CH4-based chain alkane ratio should not be used as a marker gas. This study provides experimental basis and gas index optimization scheme for the prediction and prediction of coal seam spontaneous combustion under similar geological conditions.