Osteopontin(OPN)is a secreted phosphorylation glycoprotein,which is secreted by activated macrophage,leucocyte and activated T lymphocyte.OPN universally distributes over extracellular fluid and extracellular matrix of mineralized tissues and has multiple biological functions such as immunoloregulation etc.When host is infected with Mycobacterium tuberculosis,eumycete and bacterium,OPN can switch on host immunity to resist pathogens and enduce an anti-inflammatory action,but it also can bring into phlegmonosis soon after,so OPN has two-way accommodation.The expression level of OPN can reflect immunereaction level and inflammation level when host iS infected.Today when the drug resistance of microorganism is widespreaded,the appropriate expression and application of OPN can open up an original way for the treatment of clinical infeetious diseases.