Abstract: In order to study changes in antioxidant activity of blueberry-ferment during fermentation process, reducing power, scavenging activities on hydroxyl radical, superoxide radical, DPPH radical and ABTS radical cation were investigated and their correlation with total phenolic compounds were analysed. The results of this study showed that the content of phenolic compounds varied from 1.850mg/mL to 2.308mg/mL and increased by 24.7%. Compared with the beginning of fermentation, the scavenging activities on DPPH radical, superoxide radical and ABTS radical cation were increased gradually and improved by 3.6%, 5.7% and 16.5%, respectively. The reducing power and scavenging activities on hydroxyl radical were first increased, then slightly decreased and then increased again and improved by 20.4% and 2.4% , respectively. The free -radical scavenging activities of DPPH radical, superoxide radical and ABTS radical cation were highly correlated with the content of phenolic compounds (r=0.952, 0.860, 0.975, p<0.01, respectively) . The above results suggested that blueberry-ferment had excellent antioxidant activities. The antioxidant of blueberry-ferment increased gradually during fermentation and highly correlated with phenolic compounds.