Abstract: In order to study the stability of astaxanthin from Antarctic krill shells, the retention rate of total carotenoid content in extract was determined under different conditions, such as light, temperature, acid or alkali and metal ions.The results showed that astaxanthin was quite unstable under light and degraded rapidly especially in direct sunlight.Astaxanthin had a great loss with the increasing temperature and faded intensified when the temperature reached 60~90℃.Astaxanthin was relatively stable when alkaline concentration was low, while too high acid or alkaline concentration may cause the loss of astaxanthin.Metal ions, including Na+、K+、Mg2+、Ca2+、Zn2+ and Al3+, showed little effect on astaxanthin.While Fe2+、Cu2+ and Fe3+, especially Fe3+, could obviously destroy astaxanthin.