Abstract: In this study,phosphorylation modification of Auricularia auricular polysaccharide(AAP)was explored. The conditions for the phosphorylation of Auricularia auricula polysaccharide were optimized by response surface methodology. At the same time,the antioxidant activity for phosphorylated Auricularia auricula polysaccharide(P-AAP)was still explored. The results showed that the optimal conditions for the phosphorylation of Auricularia auricular polysaccharide were the mass ratio of sodium tripolyphosphate(STPP)to sodium trimetaphosphate(STMP)in phosphorylation reagent was 5:2,the temperature 88℃,pH was 8.6 and time was 5 h. Under these conditions,the content of phosphate in polysaccharides was 9.93%.In addition,P-AAP1 were obtained through DEAE-Sepharose Fast Flow and Sephadex G-100 chromatography. And the results of antioxidant activity showed that the DPPH radical scavenging rate of P-AAP1 increased by 34.37% compared with AAP,the half inhibitory concentration(IC₅₀)was 1.07 mg/mL. And the scavenging rate of hydroxyl radical increased by 30.39% compared with AAP,the IC₅₀ was 0.91 mg/mL. The scavenging rate of superoxide anion radicals increased by 26.40% compared with AAP,and the IC₅₀ was 0.41 mg/mL. In conclution,the antioxidant activity of Auricularia auricular polysaccharide can be improved by phosphorylation modification.