Abstract: Using the isolated strain of 030224HB and a set of specific primers, the ompH gene of P. multocida was amplified by PCR. The primers were designed based on the published sequences of the ompH gene. The 1 114 bp amplified DNA fragment was cloned into pMD18-T. The sequencing result indicated that this gene was quite conservative. The ompH gene in pMD18-T was ligated into pET28b to get the expressing vector of pET28b-ompH which was then transformed into E.coli BL21. The result of SDS-PAGE shows the expressed protein is about 35 ku, resembled to the published researches. Western-blot results indicates that this protein possesses biological activity. Using the expressed protein, ELISA to detect pasteurellosis of pigs is expected to develop.