Abstract: To evaluate the effect of 17β-estradiol on the antioxidative enzymes in larvae of Perinereis aibuhitensis, we exposed the worms to 17β-estradiol at different concentrations (0.1 μg · L^-1, 1 μg · L^-1, 10 μg · L^-1, 100 μg · L^-1 and 1 000 μg · L^-1), and measured the superoxide dismutase (SOD), catalase (CAT) and glutathione S-transferase (GST) activities on 2^nd, 4^th, 6^th and 8^th day, respectively. The results show that SOD, CAT and GST activities in 10 μg · L^-1 treatment group increased significantly, and SOD and GST activities decreased notably in 1 000 μg · L^-1 treatment group on 2^nd day. SOD and GST activities were induced at different degrees in every treatment group on 4^th day. CAT and SOD activities were suppressed in lower-concentration groups (0.1 μg · L^-1 and 1 μg · L^-1) on 6^th day and in higher-concentration groups (100 μg · L^-1 and 1 000 μg · L^-1) on 6^th day, respectively(P＜0.05). CAT activity was induced at different degrees in all groups except 1 000 μg · L^-1 group (P>0.05);GST activity was suppressed in 10 μg · L^-1group; SOD activity was also suppressed in 17β-estradiol treatment groups on 8^th day. It is indicated that SOD, CAT and GST activities in P.aibuhitensis were induced by exogenous 17 β-estradiol, and the extent was related with the exposure concentration and time.