Abstract: Objective To understand the circulation of avian influenza virus in outer environment in Hunan province and provide evidence for the prevention and control of avian influenza. Methods Analysis was conducted on the outer environment surveillance data of avian influenza virus circulation in Hunan from 2009 to 2011. Results A total of 3370 environmental samples were collected and tested during this period, and the overall positive rate of avian influenza A virus was 7.0%. The positive rate of highly pathogenic H5 and H9 viruses was 2.3%. The detection peak was during winter-spring. The detection rates were high in alive poultry markets in urban and rural areas (17.8%), in poultry slaughter houses (14.1%), on chopping boards for killed poultry (17.4%) and in water used for washing poultry (15.7%). The detection rate in duck source samples (24.1%) was higher than that in chicken source samples (9.5%). Conclusion The circulation of avian influenza virus is active during winter-spring in Hunan. It is necessary to conduct target surveillance and health education among the people exposed to poultry in alive poultry markets and poultry slaughter houses. The virus detection in duck raising houses should be strengthened too.