The invention provides a hydrogenated fuel oil conversion treatment method used for hydrogenated fuel oil desulfurization. The method is characterized in that: hydrogenated fuel oil and sulfuric acidare fully mixed and contacted, and a current rotary plate type singlet state oxygen generator is utilized as a hydrogenated fuel oil conversion treatment device to perform conversion treatment on thehydrogenated fuel oil. According to the method provided by the invention, sulfur contained by the hydrogenated fuel oil converted and treated by the method can be more easily removed by a liquid-liquid extraction method.