Abstract: The outer membrane of Brucella spp is mainly composed of Lipopolysaccharide, outer membrane proteins and phospholipid. The major outer membrane proteins of Brucella spp. are characterized as potential immunogen and protective antigens. They are classified according to their molecular mass into three groups, the group 1 proteins which consists of 10 k,18 k and 19 k. In this group, Omp10, Omp16 and Omp19 are lipoproteins. 36-38 k OMPs are group 2 proteins, and 31-43 k and 25-27 k OMPs belong to the group 3 proteins, Omp25 and Omp31 are closely related to the virulence and immunogenicity of Brucella. This paper will summarize the research on these three groups of outer membrane proteins. 863 Subject, Research of marker antigen in rapid detection assay of Brucella (No.2007AA02Z410)