This study examined the effects of hypoxia and reoxygenation on antioxidant enzyme activities and the change in histological structure in with the body weight of (2.0±0.2) g. Experimental prawns were placed in a normal (control) group or hypoxia group with given dissolved oxygen of (6.0±0.2) mg/L and (2.0±0.2) mg/L, respectively. Each group was sampled in triplicate to measure the activities of antioxidant enzymes in the muscle, gill, and hepatopancreas under hypoxia at 0 h, 6 h, 12 h, and 24 h, and under reoxygenation at 1 h, 6 h, 12 h, and 24 h. The histological structures of gill, muscle, and hepatopancreas were also observed. The results showed that the activities of superoxide dismutase (SOD), glutathione peroxidase (GPX), and catalase (CAT) enzymes in the muscle, gill, and hepatopancreas from the experimental group first increased and then declined, and the activities of the three enzymes were significantly higher than those of the control group at 12 h under hypoxia stress ( < 0.05). The activities of SOD and CAT in the muscle tissue of prawns in response to reoxygenation was fluctuated over time, and the activities of GPX under reoxygenation at 24 h was significantly lower than that of the control group ( < 0.05). The activities of SOD, CAT, and GPX in gill under hypoxia at 12 h were both significantly higher than that of the control group ( < 0.05), and there was significantly higher GPX enzyme activity under reoxygenation at 24 h than that of the control group ( < 0.05). Compared with the control group, the significantly higher SOD, CAT, and GPX activities in the hepatopancreas of prawns were observed at 6 h ( < 0.05), and the content of MDA in the hepatopancreas of prawns in response to hypoxia and reoxygenation was significantly higher than that that of the control group ( < 0.05). Observation of tissue by paraffin section revealed that hypoxia and recovery did not affect muscle tissue structure. Through the observation of the tissue section of the gill, it was found that the epithelial cells and the pillar cells were disordered after 12 h of hypoxia stress, and the secondary layer was hypertrophied. After 24 h of hypoxia, the secondary layer of hypertrophy was intensified and red blood cells inflowed. The morphology of the cells changed, and the number of cells increased, but it recovered to some extent after reoxygenation. During hypoxia stress, the number of B cells in the hepatopancreatic tissues significantly decreased, but the number and apparent volume of B cells recovered to the level of the control group after reoxygenation. The results showed that acute hypoxia can cause damage to the hepatopancreas and gill of , and affect the activities of antioxidant enzymes. Furthermore, the results showed that acute hypoxia can cause damage to the hepatopancreas and gill of , and affect the activities of antioxidant enzymes. The 24 h recovery period was not sufficient for to completely recover from hypoxia stress.