Using pectinase extraction method assisted with ultrasonic treatment,the extraction technology of total flavonoids from the pomace of sea buckthorn was optimized,and furthermore,the flavonoid antioxidant activity was studied.With extract yield as target,a series of affect factors during the extraction process were studied,including enzyme dose,liquid to solid ratio,ethanol percentage,ultrasonic extraction time,extraction temperature and ultrasonic power.Moreover,the experiments of response surface optimization were carried out with enzyme loading amount,liquid to solid ratio and extraction time as variables.The final optimum extraction condition was projected as 5.1% pectinase loading amount,41∶1 liquid to solid ratio and ultrasonic extraction time 81 min.Under such a condition,the 8.91 mg/g flavonoids yield was obtained.About the flavonoid antioxidant activity,these were resulted that the scavenging rate to DPPH radical was 94.42% at 0.14 mg/mL flavonoid extract concentration of the sea buckthorn pomace;the scavenging rate of hydroxyl radical and superoxide anion were respectively 83.10% and 43.41% at 1.2 mg/mL extract concentration.Generally speaking,total flavonoids from the pomace of sea buckthorn show significant antioxidant capacity.