Abstract: Using defatted adzuki bean protein as raw material, the effects of different ultrasonic power and time on the physical and chemical properties and antioxidant function of adzuki bean protein were studied by using hydrolysis degree, foaming ability and total antioxidant capacity. After treatment with ultrasonic power of 400 W for 20 min, the hydrolysis degree and solubility of adzuki bean protein reached the maximum value, which increased from 3.39% to 21.30% and 46.77% to 79.63%, respectively. Emulsification and emulsification stability were significantly enhanced (P<0.05) and increased by 78.62%, 43.94% respectively after ultrasonic power 400 W treatment for 10 min. Compared with the blank control, when the ultrasonic power was 400 W for 10 min, the foaming ability of adzuki bean protein was the best, increased by 70.31%. When the ultrasonic power was unchanged, and the ultrasonic power extended to 20 min, the foaming stability was the strongest, increased by 11.15%. Ultrasonic treatment significantly increased the content of free sulfhydryl group (P<0.05), disulfide bond content significantly decreased (P<0.05). The total antioxidant capacity was the best (681.20 U/mL) when ultrasonic power was 160 W for 30 min, DPPH radical scavenging capacity and Fe ion reducing capacity were the best when ultrasonic power was 400 W for 10 min, which increased by 78.23% and 33.52%, respectively. Ultrasonic treatment could significantly improve the physical and chemical properties of adzuki bean protein and its antioxidant capacity.