Abstract: Objective: To obtain the pac gene encoding surface protein PAC of Streptococcus mutans(S.mutans),which was isolated from clinical strain in China,and to construct the recombinant plasmids vector containing the pac gene,which will provide further study for edible plants vaccine against dental caries.Methods: According to the sequence of pac gene,a pair of pac gene specific primers was designed and synthesized;By using PCR the target DNA fragment was amplified from genome of serotype c of S.mutans which was highest frequency of clininal isolates in China.The recombinant intermediate vector pMD18-pac was constructed through T-A cloning and identified by sequencing.Results: The sequences of cloned pac gene was high homology with that of pac gene reported from references.Conclusions: The sequence of pac gene obtained in this study can be used to further study for preparation of DNA vaccine against dentalcaries.