Abstract: Ureaplasma urealyticum （UU） is the most common pathogenic microorganisms isolated from human urogenital tract, belonging to family mycoplasmataceae molicutes class. It is isolated from the patiens′ urinary tract with non-gonococcal urethritis（NGU） by Shperd in 1954，UU can break down the urea and has its specific biochemical structure and function. Most studies showed that when UU concentration was more than 106 copy/mL in the urogenital tract，sole infection of UU can result in cinical diseases，and they contribute to the genesis and development of many clinical diseases. Recent studies confirmed that UU is associated with human papillomavirus（HPV） and human immunodeficiency virus（HIV） infection，and there is a certain relationship with the spread of HIV. Many researches has always been focused on the pathogenicity of UU，but its pathogenesis has not been elucidated. So some with UU related diseases still lack of effective control. In recent years，the role of toll-like receptors（TLRs） in activating the host innate and adaptive immune response become the hot of research，especially infectious diseases. The lipid-assosiated membrane proteins（LAMPs） of ureaplasma urealyticum can activate intracellular signal transduction pathways by TLRs，induced host cell apoptosis，which may be associated with a variety of diseases. To explore the mechanism and illuminate the process are expected to provide new method for the diagnosis and treatment of clinical related diseases.

Key words: Ureaplasma urealyticum, Membrane proteins, Toll-like receptors, Apoptosis, Signal transduction pathways