Abstract: Spirulina, a blue-green algae, is gaining increasing attent ion because of its nutritional and medicinal properties, which have close relationship with ant-i oxidat ion and free radical mechanism.In organism, the antioxidase system can effectively scavenge free radicals like O-2.Recent research indicates that organo tellurium has immunomodulating property, antitumor and ant-i cancer effects, which are similar to the functions of selenium, an essential trace mineral.We have reported that inorganic tellurium could be assimilated by both yeast and Spirulina.Moreover, our research also showed that adding different concentrations of te-l lurium to Spirulina had double effects on Spirulina, that is, tellurium would accelate the S.platensis growth when tellurium concentration was less than 2mg/L, but inhibit the S.platensis growth when tellurium concentration was bigger than 2mg/L, and S.platensis would stop growing or die when tellurium concentration was 320mg/L.Therefore,we can adjust that the stress intensity of tellurium on the growth of Spirulina by controlling the concentration of tellurium and the adding time.The objective of this study was to investigate the tellurium stress on the growth of two kinds of Spirulina, S.platensis and S.maximum, and to thoroughly characterize the changes of antioxidase system in Spirulina,which would be helpful both to the research of biological function of tellurium and the biotransformation of tellurium by Spirulina.Different concentrat ions of tellurite were added to S.platensis and S.maximum on the 5th to 10th.The effects of Te (Ô) stress on the growth, antioxidase system and lipid peroxidat ion level of S.platensis and S.maximum were investigated.It was indicated that the intensity of Te (Ô) stress could be adjusted effectively by changing the time of adding Te (Ô).As the time of adding Te (Ô) moved backwards, the intensity of Te (Ô) stress decreased and the final biomass increased gradually.The biological effects of Te (Ô) on the two species of Spirulina were related to the intensity of Te (Ô) stress and the time of the growth.The intensity of Te (Ô) stress in the test set ?(tellurite was added on the 7th to 9th) was not the lowest and the biomass was not the highest, but the contents of MDA were the lowest.It was indicated that the growth of Spirulina was the best in test set ?The activities of the antioxidase ezymes (SOD,GPX, CAT,APX and POD) had complicated changes.The act ivity of GPX was markedly increased.