Abstract: In order to understand the immune antibody level of H5, H7 and H9 subtypes avian influenza virus in poultry, the blood samples of four experimental observation stations in Neijiang city of Sichuan province, Jinan city of Shandong province, Hebi city of Henan province and Yangzhou city of Jiangsu province were analyzed by serological investigation and hemagglutination inhibition test（HI）, including two broiler farms and three layer farms. The research found that layers were immunized with H5, H7, H9（or H5 and H9） subtypes avian influenza vaccines, while broilers were only immunized with H9 subtype avian influenza vaccine. The layer farms and broilers farms had low antibody production after the immunization of avian influenza vaccine, leading to unqualified or immune failure. It is suggested that the immunization different subtypes of avian influenza vaccine and the monitoring of avian influenza antibody levels after immunization should be strengthened to prevent the occurence and prevalence of avian influenza.

Key words: broilers and laying hens, H5, H7, H9 subtypes of avian influenza vaccine, antibody level, qualified rate of immunity