Abstract: Objective:The study was to research the sterilization effect of ultrasound assisting ClO2 in the application of processing the heat-sensitive watermelon juice and the optimum technology to remove the residual ClO2.Methods:The fresh raw watermelon juice was treated with the ultrasound assisting ClO2 sterilization technology and the residual ClO2 was removed by vacuum combining with ultrasound. Evaluate the effect of sterilization process and the technical parameters of removing the residual ClO2.Results:The optimal conditions of sterilization were that the concentration of ClO2 was 77mg /L with ultrasound for 2min under the ultrasonic power of 120W. The optimal conditions of the removal of residual ClO2 were temperature 35℃, ultrasonic power 40W, pressure 2.5kPa, time 5min.Conclusion:Ultrasound could effectively improve the sterilization effect of ClO2. The sterilization time reduced from 3min to 2min.The various concentration of ClO2 removal rate can reach more than 94% by this process functioning 5minutes.