With the implementation of the International Maritime Organization (IMO) sulphur limit policy for marine fuel in 2020, residual marine fuel desulfurization technology has brought widespread attention. The heavy oil is the main component of residual marine fuel, and desulfurization technologies of heavy oil could be categorized as two types: hydrogenation and non⁃hydrogenation technologies. Hydrogenation technologies include fixed bed, ebullating bed, suspended bed, and moving bed, et al. Non⁃hydrogenation technologies include alkali metal compound treatment, selective oxidation⁃extraction/thermolysis/process intensification, electrochemical, biodesulfurization, and sodium, et al. Among these hydro⁃desulfurization technologies, fixed bed hydro⁃treating is more proper in producing residual marine fuel with the sulfur content lower than 0.5% at present. Meanwhile, to produce residual marine fuel with sulfur content lower than 0.1%, it needs to choose the low sulfur containing raw materials and/or blend oils. For non⁃hydrogenation desulfurization technologies, selective oxidation⁃ultrasound and sodium technologies can directly produce heavy fuel oil with sulfur content lower than 0.1%, while sodium desulfurization technology shows a better application prospect.