Objective:To investigate the effect of CpG ODN on the immune responses and immune-contraception induced by ZP~(121-140) synthetic peptide.Methods: BALB/e mice were given an injection into the left tibialis anterior muscle of ZP~(121-140) synthetic peptide with 20 μg CpG ODN or CFA,then the mice were given other injections at 2,4,6 weeks using the same formulation.The mice' s blood was collected before each vaccination and after the last vaccination every 2 weeks.The specific IgG and IgA in sere and non-specific cytokines IFN-γ,TNF-α,IL-10 in vaginal mucosa were measured by ELISA.The ovarial pathological changes were undertaken using hemattxylin and eosin-stained paraffin sections.Results:The specific IgG in sera and IgA in vaginal mucosa induced by ZP~(121-140) synthetic peptide combined with CpG ODN were no more than those of ZP~(121-140) synthetic peptide combined with CFA.There were significant increases in IFN-γ,and TNF-α when CpG ODN was mixed with ZP121-140 synthetic peptide and the increase of CpG ODN was more significant than that of CFA.Otherwise there was a significant decrease in IL-10 when CpG ODN was mixed with ZP~(121-140) synthetic peptide and the decrease of CpG ODN was more significant than thai of CFA.There was no significant difference in the rate of pregnancy between CpG ODN group and CFA group,but the average number of birth mice in CpG ODN group was less than that in CFA group.No pathological changes were found in the ovaries of experimental mice.Conclusion: The adjuvant effect of CpG ODN is more advantageous than that of CFA in contraception vaccine research.