Abstract: The antioxidant capacities of Lactobacillus rhamnosus ZB1107-01 ( LR ZB1107-01) and Lactobacillus rhamnosus GG ( LGG) in vitro were compared． Taking free radical scavenging activity of DPPH clearance，hydroxyl clearance and superoxide anion as the indexes and establishing the oxidative damage model of Caco-2 cells，this study investigated the effects of LR ZB1107-01 on oxidative stress of Caco-2 cells by measuring the activities of SOD and GSH-Px． The results show that the higher the concentration of bacteria，the stronger the ability of scavenging the three free radicals． The scavenging capacity of LR ZB1107-01 fermentation liquor on DPPH is significantly higher than that of LGG，the scavenging capacity of supernatant on hydroxyl radical is slightly higher than that of LGG，and the scavenging capacity of cell lysate on superoxide anion free radical is significantly higher than that of LGG． In the model of oxidative damage of Caco-2 cells，the measurement of the enzymatic activity of SOD and GSH-Px shows that LR ZB1107-01 can reduce the oxidative stress damage of Caco-2 cells and increase its antioxidant function under oxidative stress．

Key words: Lactobacillus rhamnosus, antioxidant activity, free radical, Caco-2 cell