Objective: Astaxanthin is a carotenoid found abundantly in marine foods， and its antioxidant properties are widely recognized. In recent years， the impact of oxidative stress on Alzheimer's disease(AD) has attracted more and more attention. Previous studies mainly focused on the use of astaxanthin's antioxidant effect to delay its pathological progress after the onset of AD. The aim of the present study was to explore the preventive effect of astaxanthin on AD using a rapid aging mouse model. Methods: Male SAMP8 mice were randomly divided into two groups， including control group and astaxanthin group(n=8). SAMR1 mice was used as the control group. The mice in astaxanthin group were supplemented with 40 mg/kg bw astaxanthin for 4 months. Morris water maze and open-field test were conducted to evaluate the ability of learning and memory as well as the anxiety of mice. The content of Aβ and level of oxidative stress in the brain， liver and serum were also measured. Results: Dietary astaxanthin significantly enhanced the ability of learning and memory as well as relieved the anxiety of SAMP8 mice. Moreover， astaxanthin significantly reduced the content of Aβ and impoved the level of oxidative stress in the brain. Meanwhile， dietry supplementation with astaxanthin exerted different extent of antioxidant level in the liver and serum. Conclusion: Dietary astaxanthin enhanced the ability of learning and memory by inhibiting oxidative stress in the brain and tissues of SAMP 8 mice， which might prevent or delay the occurrence of AD. These results provide a theoretical basis for exploring the neuroprotective function of astaxanthin and its application in related functional foods or dietary supplements.