Abstract: To evaluate the variations of H9N2 Avian influenza virus （AIV） in Jiangsu and Anhui Province in 2013， HA and NA genes of 4 isolates of H9N2 AIV isolated in 2013 were sequenced， DNAStar and Mega software were used for phylogenetic analysis. The results showed that their cleavage site of HA were all\|R （K） SSR/GL\|， showing typical character of low pathogenic avian influenza HA gene. But， the 226th amino acid was Leucine， showing a human influenza receptor binding characteristic. The NA genes of 4 isolates had a 9 bp deletion and their potential glycosylation sites were not more than 8. It was concluded that HA and NA genes of H9N2 AIVs isolated from Jiangsu and Anhui in 2013 had intragenic mutation， which showed a certain correlation with time， but not locations.

Key words: H9N2, HA, NA, phylogenetic analysis