Avian influenza(AI) is an infection or syndrome caused by influenza virus type A, and highly pathogenic avian influenza(HPAI) caused by subtype H5 and H7 can lead to 100% mortality in poultry. A-vian influenza virus are highly labile, because of antigenic drift and antigenic shift. Human "avian influenza" is a novel infectious disase caused by highly pathogenic avian influenza virus which cross barrier between species. It was found that avian influenza virus subtypes H5N1, H7N7 and H9N2 can infect humans, but there was no evidence for person-to-person transmission of those avian influenza A viruses. Based on intensified inspection, culling and immunization with killed vaccine can prevent avian influenza epidemic. Developing new influenza vaccine with H5, H7 or H9 subtype is an effective method to prevent human influenza pandemic.