Abstract: Four pairs of primers containing BamHⅠ and XhoⅠ sites were designed for amplification of 43 ku outer membrane protein （43K OMP） of bovine Fusobacterium necrophorum strain H05 according to the GenBank. The PCR products of the truncated 43K OMP genes were digested with BamHⅠ and XhoⅠrestriction endonuclease, and then the digested products were ligated to the pET-32a vector with His tag. The positive plasmids of four truncated 43K OMP genes were transformed into E.coli BL21(DE3). Protein expression of four truncated 43K OMP genes were induced using 1.0 mmol/L IPTG. The result indicated that the four truncated 43K OMP genes were successfully expressed in E.coli, and molecular weights of the expressed proteins were all about 30 ku. This study would provide some basis for further research of immunogenicity of the outer membrane protein of Fusobacterium necrophorum.