The oxidation of surfactant (polyoxyethylene alkyl ether, C14H29O(CH2CH2)(7)H, hereafter referred to as SS-70) induced by high power ultrasound is examined. The influences of aeration, bubble distribution, and frequency on the degradation rate are investigated. SS-70 is decomposed totally in a few hours. The optimum frequency for the degradation is observed. The decomposition rate of the surfactant is enhanced by the aeration and depends on the shape of the reactor. The optimum condition for the degradation process of ultrasonic oxidation is discussed.