Information regarding antioxidant enzymes in amphioxus remains lacking, and this study was carried out to examine the activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX) in different genders and tissues of amphioxus Branchiostoma belcheri tsingtauense.Results show that (1) CuZn-SOD, CAT and GPX activities in the whole amphioxus B. belcheri tsingtauense were basically at the same levels in male and female amphioxus, whereas both T-SOD and Mn-SOD activities in male amphioxus were significantly higher than that in the female (P＜0.05); (2) The testis had significantly higher T-SOD and CuZn-SOD activities than the ovary (P＜0.05); (3) CuZn-SOD activity was undetectable in the guts of male and female amphioxus; (4) For both male and female amphioxus, the activities of CAT and GPX in the gonads including testis and ovary were the lowest (P＜0.05)among the tissues examined; (5) The gut and gill had the same level GPX activities while the gut had a higher CAT activity; (6) There was no clear difference in CAT and GPX activities in the corresponding tissues between male and female amphioxus. The study on SOD, CAT and GPX activities in different genders and tissues of the protochordate provides data for future comparison of amphioxus antioxidant enzymes with those of invertebrates and vertebrates.