Abstract: The in vitro antioxidant capacity of the Stanuntonia Chinensis ( SC) juice was evaluated with ascorbic acid as a control and the effection of inhibiting and non-inhibiting browning juice on antioxidant capacity was tested through comparison with fresh juice.The results showed that the total reducing power ( TRP) and the scavenging ratio of ·OH, O₂^-·and nitrite of 100%SC juice was 7.26%, 7.29%, 11.80%, 9.92% lower than that of 0.8 mg/m L ascorbic acid ( p < 0.01) , but the blocking synthesis of nitrosamine ( BSN) showed no significant difference with ascorbic acid's ( p = 0.5714) .The TRP, scavenging ratio of·OH, O₂^-·, nitriteand BSN of fresh juice was 19.65%, 100.50%, 22.31%, 20.62%, 13.33% higher than of the non inhibiting browningjuice's ( p < 0.01) . The TRP, scavenging ratio of nitriteand BSN of inhibiting browning juice showed no significant difference with fresh juice ( p > 0.05) , and the scavenging ratio of·OH and O₂^-·was 2.74% and 6.95% lower than fresh juice's ( p < 0.01) . The SC juice has strong antioxidant ability, the browning reduces the antioxidant capacity and inhibition of browning can better preserve the antioxidant activity of the SC juice.