Abstract: This study used oats as raw material to extract oat protein, and investigated the effects of different ultrasonic power（100, 200, 300, 400 W）, as well as multiple ultrasonic treatment time（5, 10, 15, 20, 25, 30 min）on its soluble protein content, oil retention, emulsification, nitrogen solubility index, DPPH free radical scavenging rate, and ABTS cation free radical scavenging rate. Experimental results suggested the optimal ultrasonic treatment condition was 200 W ultrasonic treatment for 15 min, which resulted in the soluble protein content was 67.92 mg/g,the oil holding capacity was 2.04 g/g, the emulsifying property was 49.82%, the nitrogen solubility index was28.91%, with 88.03% and 81.93% for the scavenging rates of DPPH free radical and ABTS cation free radical respectively. This study demonstrated appropriate ultrasonic treatment could effectively increase the soluble protein content of oat, and improve the functional properties and antioxidant activity of oat protein.