The work aims to investigate the sterilization effect and changes of storage quality of crayfish treated by ultrasound and slightly acidic electrolyzed water (US-SAEW). The effects of available chlorine concentration (ACC) of SAEW, soaking time, and US power on microorganisms were evaluated. The effect of combined treatment on the total bacteria, total volatile base nitrogen (TVB-N), malondialdehyde (MDA), color difference, and sensory characteristics of crayfish during storage at 4°C were analyzed. The results showed that when the crayfish were treated with US-SAEW at ACC of 60 mg/L, and ultrasonic power of 405 W for 10 min, the total bacteria of crayfish decreased by 1.48 lg CFU/g compared with the blank group, indicating a stronger bactericidal effect compared with the single treatment. During the cold storage, the growth of the total bacteria was inhibited by US-SAEW, and the rate of increase in total volatile base nitrogen and malondialdehyde was lower than that of the blank group, which showed a positive effect on delaying the fat oxidation and spoilage of samples. Thus, compared with the control group, US-SAEW treatment has a good bactericidal effect, which could better maintain the quality of crayfish and extend the refrigerated shelf life by at least 4 days.