Degradation of hazardous organic compounds using ultrasound is an attractive advanced oxidation technology for wastewater treatment, and it is well known that the ultrasonic degradation reaction is enhanced by particle addition. In this study, the effects of ultrasonic irradiation conditions and particle addition on the degradation rate constant were investigated using pseudo-first-order chemical reaction model. Moreover, the application of this model to degradation of other organic compounds in the presence of particles by other research groups has been investigated. The degradation reaction was enhanced by particle addition, and the apparent degradation rate constant is proportional to the increase in amount of particle. In addition, the constant of proportionality is not influenced by degraded material and ultrasonic frequency. However, particle type influences the constant of proportionality.