Abstract: Phenolic compouds and antioxidant activity of 9 cultivars sweet potato juice were investigated to provide reference for the utilization of sweet potato juice.The amount of flavonoids, total phenolics content and total anthocyanins content of sweet potato juice were determined using Folin-Ciocalteu method, Sodium nitrite method and pH differential method respectively.The result showed that phenolic compouds were rich in sweet potato juice and amount of flavonoids, total phenolics and anthocyanins were variant in different cultivar of sweet potato juice.The antioxidant activity of sweet potato juice was evaluated by means of four vitro antioxidant systems (FRAP, DPPH, ABTS+ and OH radical scavenging method) .Results indicated that different cultivars of sweet potato juice had different antioxidant activities and cultivars containing higher amount of total phenolics had higher antioxidant activities.Cultivars of Hangyinshu 1, Hangyinshu 3, Zhezishu 1 and Zheshu 13, which had higher antioxidant activitiy were more appropriate for juice processing and functional beverage development in terms of antioxidant activity.