In order to study the influence of the micromorphology and spontaneous combustion characteristics of polysufide on coal, the true density, porosity, micromorphology and oxygen uptake of coal samples with different sulfur content were tested. The results show that the porosity of coal sample increases with the increase of sulfur content; and adding of FeS2 and FeS to the original coal samples, the fine particles on the surface were increased; after oxidation and heating, the massive coal body was broken into several fine particles, which promoted the spontaneous combustion of coal; the effect of FeS on promoting the low-temperature oxygen absorption and shortening the natural combustion period of coal was slightly greater than that of FeS2; under the same coal temperature condition, the CO production increased first and then decreased with the increase of sulfur content, and when the sulfur content was 3% and 4%, the production of CO and C2H4 was the largest.