To develop efficient porcine circovirus type 2(PCV2) vaccine,the mucosal immune effect of PCV2 Cap protein epitope recombinant replication-deficient adenovirus(rAd/Cap/518) was evaluated.The Balb/c mice were immunized by oral,intramuscular and intranasal routes with rAd/Cap/518,and the mice were immunized by intranasal routes with wild rads without exogenous genes as the control group.IgG in serum,IgA antibody in saliva,lung and intestinal lavage fluid,secretion of T lymphocyte subsets and related cytokines IFN-γ and IL-4 in spleen,and PCV2 viral load in lymph nodes,spleen and lung were detected.The results showed that,compared with the control group,the level of serum IgG antibody induced by rAd/Cap/518 via intramuscular route increased significantly.The level of IgA antibody in local mucosa significantly increased by intranasal and oral immunization.The percentage of CD3+T cells induced by rAd/Cap/518 was 46.60%—55.65% by intranasal, intramuscular and oral routes.The percentage of CD3+CD4+T cells was 34.43%—37.29%,the percentage of CD3+CD4+T cells induced by intramuscular and oral immunization was 36.35%—41.58%,the percentage of CD3+CD8+T cells induced by intranasal immunization was 12.39%—18.32%,and the percentage of CD8+T cells induced by oral immunization was 16.29%, which were significantly higher than that of the control group.Intranasal immunization with rAd/Cap/518 could induce IFN-γ production in spleen and mesenteric lymphocytes.The virus load of immunized mice decreased significantly.These results indicate that rAd/Cap/518 mainly induces systemic immune response via intramuscular immunization,and systemic and local mucosal immune response via intranasal and oral immunization. It is a promising mucosal vaccine candidate for PCV2.