Abstract: This dissertation studies the corrosion mechanism of active sulphur on different types of tanks and how ferrous sulfide is produced on the basis of analyzing the typical spontaneous combustion cases of sulphur containing oil tanks, and then points out the accident is resulted from the corrosion product ferrous sulfide that can oxidizes and sends out heat subsequently. Furthermore, on the foundation of deeply investigating the spontaneous combustion reason of ferrous sulfide and taking practical application of project into account, the paper puts forward two main methods to prevent ferrous sulfide from spontaneous combusting and eliminate ferrous sulfide: (1) eliminate sulphur produced in the process of refining petroleum; (2) purge ferrous sulfide or transform ferrous sulfide into other form, proposing corresponding requirements on the facets of technology and safety management at the same time.