Some antioxidant enzymes in hepatopancreas were examined to evaluate the damage of the dietary AFB₁ on antioxidant enzyme in hepatopancreas of juvenile Litopenaeus vannamei. Two kinds of diets (control diet and test diet containing 2000 μg/kg of aflatoxin B₁) were fed to the shrimp[with body weight (0.3±0.02) g] for 4 weeks. 420 shrimps were selected randomly to 6 aquariums (40 cm ×50 cm ×60 cm).The activity of some antioxidant enzymes in hepatopancreas were determined every four days. The results showed that the activity of SOD of test group was significantly lower than that in control group on the 8th day. In two weeks the activity of SOD decreased significantly, and the activity of test group was significantly lower than that in control group. The activity of CAT significantly decreased in each stage. After 8 days, the activity of CAT in test group was lower than control group, especially, the activity of test group was significantly lower than control group on the 8th, 16th and 24th days. Although there was a rising trend after 20 days, the CAT activity showed significant decline from the original value.The activity of GSH-Px was lower than that in the control group, with the ability of repairing themselves decreasing. The content of MDA increased significantly after 16 days and there was a rising trend. Meanwhile, the content of MDA in test group was significantly higher than that in control group. These results indicate that the damage of high concentrations of AFB₁ on antioxidant enzyme in L. vannamei varies with different enzymes, and the damage on hepatopancreas continues to increase, causing severe hepatopancreas damage only in 4 weeks.