Novel goose astrovirus (NGAstV) is a member of the genusAvain Avastrovirus(AAstV) and the familyAstroviridae. NGAstV-associated gout disease has caused huge economic losses to the goose industry worldwide. Since early 2020, NGAstV infections characterized by articular and visceral gout emerged continuously in China. Herein, we isolated a GAstV strain from goslings with fatal gout disease and sequenced its complete genome nucleotide sequence. Then we conducted systematic genetic diversity and evolutionary analysis. The results demonstrated that two genotypic species of GAstV (GAstV-I and GAstV-II) were circulating in China, and GAstV-II sub-genotype IId had become the dominant one. Multiple alignments of amino acid sequences of GAstV capsid protein revealed that several characteristic mutations (E456D, A464N, and L540Q) in GAstV-II d strains, as well as additional residues in the newly identified isolate which varied over time. These findings enrich the understanding of the genetic diversity and evolution of GAstV and may facilitate the development of effective preventive strategies.