Effect of astaxanthin from phaffia rhodozyma (prepared in our laboratory) on the oxidative stability of oil was studied. The astaxanthin was selected as antioxidant, and peroxide value (POV) and acid value (AV) as the main indexes. The antioxidant activity was studied, compared with common antioxidates, such as TBHQ，BHA and BHT. The results showed that astaxanthin was an oil antioxidant, whose effect was a little better than that of TBHQ, much higher than that of BHA and BHT on tea oil,and the effect on tea oil was obvious in dose-effect relationship. When the adding amount was 0.015%, the antioxidant effect of astaxanthin from phaffia rhodozyma was good. Astaxanthin from phaffia rhodozyma is a natural antioxidant, which has potential antioxidant application value to tea oil.