Abstract: Superoxide dismutase (SOD) and peroxidase (POD) are two important anti- oxidation enzymes that exist widely in tissues of aerobic and anaerobic creatures. SOD and POD have been taken as two immune enzymes and a marker with several other related enzymes in evaluating crustacean animals’ immune function. Litopenaeus vannamei is Chinese major raised aquatic shrimp, and Virus is a major reason for the spreading of epidemic Litopenaeus vannamei diseases. To improve the own immunity of Litopenaeus vannamei and enhance its anti-virus function become the basic method of comprehensive prevention and cure. Therefore, people pay more and more attention to study the immunity factors of Litopenaeus vannamei and improve their anti-diseases ability effectively.The activities and location of superoxide dismutase (SOD) and peroxidase (POD) in the liver, muscle, heart, eye and gill of Litopenaeus vannamei were studied with enzyme cytochemical technique of electronic microscope, compared with the infected shrimp. The results showed that SOD positive reactions were mainly deposited in mitochondrium membrane and cytoplasm in the cells of the liver, muscle, heart and gill of the healthy shrimp. Furthermore, SOD activity was located around lipid droplet in liver. POD positive reactions were mainly deposited in specific organelle: peroxisome in the cells of the liver, heart and gill respectively. There were also POD positive granules around lipid droplet in liver. In the infected shrimp, the obviously histopathological changes were detected in five tissues, and more myelin figures appeared in the cell of each tissue and the number of the fat drops in liver cells sharply reduced. There were evident differences in tissues between diseased shrimp and healthy shrimp in the activities and location of SOD and POD. SOD positive granules in cytoplasm of the muscle, heart and gill of the infected shrimp disappeared; and the activities of SOD in liver decreased. At the same time, SOD positive reactions were also found in mitochondrial matrix of heart and gill. POD positive reactions were still found in peroxisome of the liver, heart and gill. But the number of peroxisome positive reactions in liver and gill got decreased; POD positive granules around lipid droplet in liver almost disappeared; part of peroxisomes in heart disintegrated and lots of positive-reacting granules scattered in cytoplasm.The results indicated that the activities and distribution of SOD and POD isozyme in Litopenaeus vannamei cells had clear tissue-specific, and SOD and POD played an important role in defense oxygen toxicity injury and the immune function of Litopenaeus vannamei. Our study will provide theoretical foundation for the application of immune technology in disease prevention and control in Litopenaeus vannamei in future.