Abstract: In order to explore the purification process of crayfish, ultrasonic cleaning technology and slightly acidic electrolyzed water bacteria reduction technology were used to purify living crayfish. In this paper, the total number of colonies and spores, the turbidity of the cleaning solution were used as evaluation indicators, and the available chlorine concentration of slightly acidic electrolyzed water, soaking time and ultrasonic power were single factor levels. The antibacterial effect of slightly acid electrolyzed water and the cleaning effect of ultrasonic technology on crayfish were studied. The results showed that the higher effective chlorine mass concentration of slightly acidic electrolyzed water, the longer treatment time, the better bacteria reduction effect. When the effective chlorine concentration of slightly acidic electrolyzed water was 60 mg/L, the total number of colonies and the total number of spores decreased by 4.26 lg CFU/g and 500 CFU/g after 50 minutes of treatment of crayfish, and the bacteria reduction rate reached 99.99% and 92.61%. The survival rate of crayfish was 100% after treatment with 50 W ultrasonic power for 50 min, and the turbidity of the cleaning solution was 181 NTU, which was significantly better than the control group (P<0.05). After synergistic work of ultrasonic technology and slightly acidic electrolyzed water in purify living crayfish, the initial bacteria of crayfish was decreased from 7.17 lg CFU/g to 3.52 lg CFU/g and the bacteria reduction rate was reached 99.98%, which was significantly better than the bubble cleaning process in workshop (P<0.05). There was no significant difference in the nutritional value and quality of crayfish after purification (P>0.05), and the process was reasonable and effective.