Abstract: The mechanism of ultrasonic desorption of sulfur dioxide from citrate solution was investigated mathematically based on the characteristics of ultrasonic wave. The factors influencing ultrasonic desorption of sulfur dioxide were discussed theoretically and the mechanism was verified by experiments. The results showed that it was feasible to remove sulfur dioxide from citrate solution with ultrasonic field in theory and on the laboratory scale. There was a greater effect of ultrasonic frequency and gas content in solution as well as solution properties on sulfur dioxide desorption. The sulfur dioxide desorption efficiency could be improved rapidly by introducing cavitation bubble nucleus, such as adding trace argon gas. A lower ultrasonic frequency might result in higher desorption efficiency. Giving a proper stirring to the solution, the SO2 desorption efficiency enhancement could be increased by 20%—30% over the control value. The higher the initial concentration of sulfur dioxide in citrate , the higher the desorption efficiency.