Abstract: Based on single factor experiment, three main factors were creened out, including the ultrasonic time, ultrasonic power, ultrasonic temperature. Optimization of these factors by using response surface methodology was studied. Results of response surface analysis showed that the optimum ultrasonic extraction conditions of SOD were as follows : ultrasonic time 15min , ultrasonic power 220W , the ultrasonic temperature 31 ℃ . Under these conditions, specific activity of SOD was 77.5U/mg and which was in good agreement with the predicted value.