Fusion expression plasmid pFBPS, pFBPS (7 - 82), pFBPS (7 - 165) and pFBPS3 (87 - 320) of Streptococcus suis type strain HA9801 were generated by cloning different fragments of fbps amplified from pMD-T-FBPS by PCR into plasmid pET-32a(+). It has been confirmed that the recombinant proteins, FBPS, FBPS(87 -320), and FBPS(7 - 167), which are expressed by recombinant plasmid pFBPS, pFBPS(87 - 320) and pFBPS(7 - 165), respectively, bound human fibronectin by ligand affinity Western blot assay. The results indicate the primary fibronectin-binding domain of FBPS lies within 87 - 165 amino acid residues region.