Abstract: In this study, the basic quality parameters (pH, soluble solid content, soluble sugar content and titratable acid content) and the contents of major bioactive components (ascorbic acid, total flavonoids, and total phenolics) of fruit juice from 20 different wampee (Clausena lansium) cultivars were determined. Meanwhile their antioxidant activities were also evaluated based on 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging and ferric reducing antioxidant power (FRAP) assays. Moreover, the correlation of antioxidant activities with ascorbic acid, total flavonoids and total phenolics contents were explored. The results showed that significant differences in pH, soluble solid content, soluble sugar content, titratable acid content, sugar/acid ratio, ascorbic acid content, total flavonoids content, total phenolics content, DPPH radical scavenging capacity and FRAP antioxidant capacity existed among the 20 wampee cultivars. The Q cluster analysis showed that the 20 wampee cultivars were divided into 3 groups based on the above physicochemical indices. Both DPPH scavenging capacity and FRAP antioxidant capacity were significantly positively correlated with the contents of ascorbic acid, total flavonoids and total phenolics, suggesting that antioxidation of wampee fruit juice was closely correlated with its bioactive composition of ascorbic acid, total flavonoids and total phenolics.