An open reading fragment, SSU2099, encoding pilus gene from srtBCD pilus island was identified based on bioinformatics analysis of the genome sequence of 05ZYH33 and alignment with relative protein family. The target DNA fragment was amplified using a pair of primers specific to SSU2099 gene. SSU2099 gene was cloned into prokaryotic expression plasmid pET32a subsequently, and the recombinant protein was expressed and purified. The mice anti-SSU2099 serum was obtained by immunizing mice with recombinant SSU2099 protein, and the titer of the serum was analyzed by ELISA. Animal test showed that vaccinating mice with recombinant SSU2099 confer a significant protection, which indicated that SSU2099 can serve as a novel vaccine candidate. Further studying of the localization and function of SSU2099 may adds novel insights into the role that srtBCD pilus island plays in pathogenicity of Streptococcus suis 2.