This work presents the results obtained in the development of phosphotungstic acid/semi-coke catalysts in the oxidative desulfurization (ODS) process of diesel oil using hydrogen peroxide as the oxidizing agent. Phosphotungstic acid /semi-coke (60wt%) prepared by impregnation. These catalysts were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM), The effect of the amount of catalyst used , on the efficiency of desulfurization was investigated. In addtion. the diesel after oxidation and extraction was analyzed by GC-FPD for sulfur content. The chromatograph shows that virtually all the sulfur containing compounds in diesel were removed.