Abstract: Taking flagellin as carrier protein, by chemical coupling to Staphylococcus aureus type 5 capsular polysaccharides, we tested the protective effect of polysaccharide vaccine on mouse model for breast. Mice were divided to 4 groups with 10 mice in each, they were immunized with saline, 10 μg CP5 alone, 10 μg CP5 conjugated with BSA (BSA-CP5), 10 μg CP5 conjugated with flagellin (flagellin-CP5) respectively on the first day and the 21th day. Two weeks after the second immunization, mice were challenged with S.aureus in peritoneal or breast, and cytokines expression of IL-4, IL-10, IFN- r, IL-12 in breast tissue were quantified by real-time PCR. The results showed that the CP5 conjugated with flagellin vaccine had a protective effect on mice breast, and induced Th1 cytokines expression in breast tissue, suggestting that flagellin was an ideal carrier protein for CP5.