The experiment was designed to evaluate the effects of temperature (16,19,22,25,28℃) and salinity (5,10,15,20,25) on the activity of total superoxide dismutase(T-SOD), glutathione peroxidase(GSH-PX) and maleic dialdehyde (MDA) of Daphniopsis tibetana Sars by means of the experimental ecology method under the laboratory conditions. The results showed that stress responses to temperature and salinity were induced in the D. tibetana.The activities of SOD,GPX and the content of MDA increased with temperature and salinity raised. After 24h-stress, the maxima were (37.18±1.97)U mg^-1 μg^-1,(75.10±9.96)U mg^-1 μg^-1 and (12.24±2.12)nmol mg^-1 μg^-1, respectively, when the temperature and salinity simultaneously reached 28℃ and 20;48 hours later, the activities of SOD,GPX and the content of MDA in the groups of high temperature of 25 and 28℃ except for those held at salinity of 15 were significantly higher than the others. While the maxima of (19.25±3.48)U mg^-1 μg^-1, (59.95±4.66)U mg^-1 μg^-1, (4.98±0.66)nmol mg^-1 μg^-1, respectively,were observed in the group of temperature of 28℃ and salinity of 5. The above results indicated that there were significant affects of temperature and salinity on the antioxidant enzymatic activities(SOD, GPX) and lipid peroxidation(MDA) in D.tibetana (P<0.01).