Photochemical desulfurization of light oils of different sulfur contents and aromatic components, such as straight-run light gas oil (LGO) and light cycle oil (LCO), in an oil/hydrogen peroxide aqueous solution two-phase liquid-liquid extraction system is investigated. The entire wavelength region of light from a high-pressure mercury lamp was utilized to realize the direct excitation of sulfur-containing compounds. In the case of LGO of high sulfur content, 77% of the sulfur is removed by 36 h of photoirradiation, and the quantity of sulfur removed from LGO is six-fold greater than that in the case of commercial light oil (CLO), Although the desulfurization of LCO is suppressed by the presence of large quantity of 2-ring aromatics, the sulfur content is reduced to less than 0.05 wt% to meet with regulations in Japan. GC-AED analysis shows that benzothiophenes in all the feedstocks are more easily desulfurized than dibenzothiophenes. Highly substituted dibenzothiophenes in LCO, especially those having substituted carbon number of 4-6, are hardly desulfurized by the proposed method.