In order to identify the contamination and distribution of avian influenza virus（AIV）in poultry-related external environment in Yunnan Province，6 types of environmental samples collected from 139 monitoring points in 16 prefectures（municipalities）in the province were detected for AIV nucleic acids by fluorescence quantitative PCR from 2019 to 2022，and the positive samples were genotyped into H5，H7，H9 and other subtypes. The results showed that a total of 3 235 environmental samples were detected in 139 monitoring points across the province，and 1 124 positive samples were identified，with a total positive rate of 34.74 %；H5 subtype，H7 subtype，H9 subtype，the untyped as well as H5 and H9 mixture，accounted for 3.02%，0.36%，88.88%，3.47% and 4.27%，respectively，indicating differences with statistical significance（χ2 = 146.66，P＜0.05）；the positive rates were 28.76%，26.31%，38.06% and 41.65%，respectively in the four successive years，with significant differences among different years（χ2 = 56.86，P＜0.001）；for the types of samples，their positive rates were successively ranked from high to low as follows：wiped samples from cage surface（41.82%），wiped samples from butcher boards or counters for displaying poultry meat（40.71%），drinking water for poultry（30.02%）and poultry feces（21.14%），and the overall difference of all their positive rates was statistically significant（χ2 = 146.66，P＜0.05）；for different premises，their positive rates were successively ranked from high to low as follows：urban and rural live poultry markets（43.16%），wild bird habitats（14.83%），scaled poultry farms（14.6%），backyard poultry farms（14.11%），poultry slaughtering and processing plants（0），which were different with statistical significance（χ2 = 263.71，P＜0.001）；the positive rate of the 16 prefectures（municipalities）ranged from 14.24% to 69.62%，and was higher in Honghe Prefecture（69.62%），Dehong Prefecture（59.23%）and Xishuangbanna Prefecture（48.23%），indicating statistical differences（χ2 = 213.06，P＜0.001）. In conclusion，poultry related external environment was seriously，widely and increasingly contaminated with AIV in Yunnan Province；complex serotypes were detected，especially H9 subtype was dominant；live poultry markets were most seriously and considered as the areas with high risk. Therefore，monitoring of AIV and management of live poultry markets should be improved to reduce possible risk of occurrence.