Objective:To investigate the optimal dose of Th1/Th2 immuno-enhancement effects of cultivated Artemisia rupestris L. crude polysaccharides (CARCP) on foot-and-mouth disease vaccine (FMDV) via the intramuscular route. Methods:ICR mice were intramuscularly immunized twice with different concentrations of CARCP mixed with FMDV at 2-week intervals. FMDV-specific antibodies, isotypes, and IgE in serum were detected by ELISA. Splenocyte proliferation was detected by MTT. T lymphocyte subsets and cytokines in the spleen were detected by flow cytometry. Clinical signs and local reactions at the injection site were monitored daily, and the body weight of mice was weighed after immunization.Results:The medium dose of CARCP could significantly improve FMDV-specific IgG, IgG 1, and IgG 2a antibody levels and the IgG 2a/IgG 1 ratio ( P<0.05) and lead to significant splenocyte proliferative responses ( P<0.01). The medium dose of CARCP could also significantly increase the level of CD3 +CD4 + and CD3 +CD8 + T cells as well as CD4 +/CD8 + ratio ( P<0.05), elicited the higher levels of IFN-γ in CD4 + T cells and CD8 + T cells ( P<0.05). No local adverse reactions at the injection site were observed after immunization. There was no significant difference in body weight or growth between each group( P>0.05). CARCP did not significantly induce an IgE response ( P>0.05). Conclusions:CARCP as an FMDV adjuvant promotes Th1/Th2 immune responses, especially in favor of the Th1 response, and has a certain safety profile. The best immune enhancement is achieved with CARCP at medium doses.