To study the immunoadjuvant effect of ursolic acid (UA) co-immunized with murine H22 hepatocarcinoma cell vaccine. The mice were injected lysate of H22 hepatocarcinoma cell and UA co-culture as vaccine three times. After one week of the last immunization the H22 cell model were set up. The tumor growth curve and survival rate of the mice were observed. The proliferations of T lymphocytes were measured by MTT and the levels of serum cytokines IL-2 and IL-4 were determined by ELISA. CD4~+, CD8~+ lymphocyte populations were determined by flow cytometry. The serum antitumor specific antibody were determined by immunofluorescence, ELISA and Western blot. It showed that after the mice were immunized with the tumor vaccines treated with UA as immunoadjuvant. Compared with model group, the tumor growth was inhibited obviously (P<0.05), the life span of vaccine group was significantly prolonged (P<0.01). The T and B lymphocyte proliferations were significantly promoted (P<0.01), the ratio of CD4~+/CD8~+ was promoted obviously (P<0.01) and the levels of serum cytokines IL-2 and IL-4 significantly higher (P<0.01).The specific binding of antiserum and antigen was found and the higher levels of serum antibody was detected. It is concluded that UA as adjuvant could remarkably improves the immunogenicity of H22 tumor vaccines and the mice cellular immunity and humoral immunity could enhance on antitumor.