Abstract: The effects of selenium on the growth performance and immune activity of Penaeus vannamei are explored. Selenium-enriched yeast was added to animal feed to prepare different concentrations of organic selenium feed. After the animals were fed, the physiological indicators and antioxidant enzyme activities were detected. The results were as follows: the growth performance and antioxidative enzyme activity of young P. vannamei in the experimental group showed an upward trend. In the 0.6 μg/g selenium-enriched group, the body weight reached the maximum of 0.469 g, it was 1.47 times that of the blank control group, with a significant difference (P<0.05). The maximum body length of 2.50 cm in the experimental group was 0.38 cm higher than the 2.12 cm in the control group, and the growth rate reached 17%. The glutathione peroxidase maximum in the experimental group was significantly different from that in the control group (P<0.05). In enzyme activity, the maximum value was 165.591 U/mL, an increased by 191% compared with 56.874 U/mL of the control group. Compared with the control group, the best group of catalase activity had an increase by 79% The above results showed that organic selenium feed could promote the growth of body length and body weight of P. vannamei, and increase the activity of glutathione peroxidase and catalase.