Abstract: Following genomes from various strains of Chlamydia spp being sequenced, it was found that there were only tiny changes in their gene components, the infected host variety and pathogenisis process were very different. At presence, the genomes from Chlamydia trachomatis, C.muridarum, C .pneumoniae, Chlamydophila caviae were studied in detail, which revealed the relationship of chlamydial genomes and multiple members causes. The discovery of polymorphic membrane protein gene family, type III secretion gene and peptidoglycan coding gene showed the great research success in the field. After the complete nucleotide acids of various species and strains of Chlamydia spp were sequenced the many proteins were further knew, involving the outer membrane protein, major outer membrane protein, hot shock protein and polymorphic membrane protein with different functions and structures. Fully understanding the properties of these proteins is in favor of studying mechanisms of pathogenisis and immunity of Chlamydia as well as high-effective gene engineering vaccine against chlamydiosis.