Abstract:The ultrasonic-assisted enzymatic method was used to extract the anthocyanin from purple potato in order to increase the yield of anthocyanins.Under the condition the mass ratio of cellulose and α-amylase was 1∶1，the best technology for extracting anthocyanins from purple potato was as follows：solid to liquid ratio 1∶30（g/mL），enzyme quantity 4 mg/g，extraction time 40 min，extraction temperature 55 ℃.The ability of scavenging hydroxyl radicals of purple potato anthocyanin was investigated.The results showed that the anthocyanin had a good performance in scavenging hydroxyl radical，when the concentration was 5 mg/mL，the free radical scavenging rate was close to 100%，which was similar to that of ascorbic acid.