Since February 2022，the outbreaks of highly pathogenic avian influenza（H5N1 subtype）caused by branch 2.3.4.4b had continuously occurred in the United States，which had made nearly 48 million poultry killed，bringing huge losses to local poultry industry and drawing concerns from the whole world. It was indicated that，through the genetic evolution，the prevalent strain was closely related to the homochronous one in Europe，but relatively independent. The strains prevalent in North America and Europe belonged to the same branch as the Re-14 vaccine strain in China，and their homology of HA gene amino acid was high（from 98.6% to 99.5%）；in the United States，red foxes and other mammals were infected with H5N1 subtype virus. For the outbreaks in the United States，many warnings and impacts were brought to the prevention and control of avian influenza in China. Based on actual conditions in China，some targeted measures were proposed in the paper，such as strengthening analysis on epidemic information，and increasing monitoring of wild animals and pathogen variation.