Abstract: An experiment was conducted to express transferrinbinding protein A (TbpA) of Haemophilus parasuis (HPS) and investigate its immunogenicity. Three pairs of specific primers were designed according to the tbpA gene sequence of HPS SH0165 strain from GenBank, three fragments of tbpA1, tbpA2 and tbpA3 containing multiple antigen epitopes were accquired by PCR and cloned into pET32a(+) vector respectively. It was confirmed that three fragments were inserted into the prokaryotic expression vector correctly by using Restriction endonuclease digestion and sequencing. The plasmids were transformed into E. coli BL21(DE3) and expressed by induction of IPTG. The specific proteins were determined by SDSPAGE and their immune activity was analyzed by Western blotting. The immunogenicity of the proteins was analyzed by vaccination efficacy assessment in mice and bctericidal assays. The results showed that three fragments of 1 140, 897 and 666 bp were amplified by PCR and expressed proteins with the sizes of 62, 54 and 44 kD. The rTbpA1 can partly protect mice from the challenge of H. parasuis LJ3 strain and a significant bactericidal activity was also detected. These results indicated that the successfully expressed rTbpA1, rTbpA2 and rTbpA3 proteins were of effective reactogenicity, and the rTbpA1 could induces an immune response and might be useful as an antigen for vaccine and serological detection against Glsser's disease.