Abstract: The middle and high sulfur coal accounts for a large proportion in Guizhou province. In order to realize the clean utilization of coal and study the genesis of high sulfur in coal, the occurrence characteristics of sulfur in main recoverable coal seams in Nuodong Exporlation Area was analyzed by using borehole data and co re test data. The formation of high pyritic sulfur and peat forming environment evolution were also discussed. The results suggested that the sulfur contents of recovera ble seams in this area were considerably high, which was attributed to the influences of seawater and post- magmatic hydrothermal activity of Emeishan basalt. The iro n and sulfur, as the materials for the precipitation of pyrite, were obtained from Emeishan basalt in the depositional basement and seawater. Besides, epigenetic pyrite had been found and theoretically derived from the intensively hydrothermal activity. The differences of distribution of sulfur content within coal seams are distinguished and attributed to seawater erosion. This conclusion is further confirmed by lagoon- tidal flat peat forming environment and the distribution character of sandstone.