The influences of ultrasonic intensity, H(2)O(2) concentration, ratio of H(2)O(2) to oil and the addition of Fenton reagent on the oxidative desulfurization of diesel oil under ultrasonic irradiation were investigated. It was observed that the oxidative desulfurization of diesel oil fitted pseudo-first-order kinetics under our experimental conditions. Increasing the ultrasonic intensity increased the oxidative desulfurization efficiency of diesel oil. The addition of H(2)O(2) enhanced the ultrasonic oxidative desulfurization efficiency of diesel oil. The sono-oxidation treatment in combination with Fenton reagent showed a synergistic effect for diesel oil desulfurization. The catalytic oxidative desulfurization process under ultrasonic irradiation process on diesel oils is an efficient and promising method.