Abstract: In order to study the effect of sulfur on coal spontaneous combustion process, in a typical Yima long-flame coal as an example, the spontaneous combustion tendency and spontaneous combustion characteristics of coal spontaneous combustion with different FeS2 contents were measured by coal oxidation dynamics. The effect of FeS2 on the oxidation of coal was analyzed, and the effect of sulfur on the thermal properties of coal spontaneous combustion was explained from the viewpoint of coal-based element reaction. The study showed that the oxidation of coal was retarded by FeS2 in the low temperature stage, and it was positively correlated with the addition amount; In the accelerating stage, the oxidation of coal was promoted, and then increased with the increase of the amount of FeS2.And the critical value of coal spontaneous combustion propensity was 5%. FeS2 mixed coal with water and oxygen chemical exothermic reaction, inspired the primitive reaction, and promoting CO, CO2, CxHy and other original gas desorption and active group oxidation of self-reactive gas generating, and the generation and rate of both greater than coal.