Abstract: Objective: The extraction process of alkali-extracted abalone viscera polysaccharides (Aavp) was optimized, and the preventive and repair effects of purified Aavp on H₂O₂ oxidative damage on L929 cells were studied to provide a reference for the development and application of Aavps. Methods: Crude Aavp was obtained by hot alkali extraction followed by alcohol precipitation, and its extraction process was optimized by the response surface method. The preventive and repair abilities of H₂O₂ oxidative damage on L929 cells were analyzed. Resulst: The optimum extraction conditions of crude Aavps were as follows: Solid-liquid ratio of 1:150 g/mL, extraction time of 2 h, and extraction temperature of 70 ℃. Under these optimal conditions, the yield of crude Aavp was 8.57%. In the prevention test of H₂O₂ oxidative damage on L929 cells, different doses of purified Aavp (20, 50 and 100 μg/mL) had a significant preventive effect on L929 cell oxidative damage (P<0.001) but did not show a dose effect. The cell survival rate of the middle dose group (50 μg/mL) was the highest (71.94%±3.08%), which was slightly better than the positive control vitamin E group but not significant. In the repair test, different doses of purified Aavp (20, 50 and 100 μg/mL) had a significant repair effect on the oxidative damage of L929 cells (P<0.001) and showed a dose effect. In contrast, the cell survival rate of the high-dose group (100 μg/mL) was the highest (90.93%±1.17%), slightly higher than that of the positive control vitamin E group (87.96%±3.05%). The results showed that purified Aavp showed an excellent preventive and repair effect on H₂O₂ oxidative damage in L929 cells. Conclusion: Aavp has an ability to repair H₂O₂ oxidative damage of L929 cells.