Objective To study the composition of variant and point mutations of Norovirus GⅡ.4 in Guiyang regions.Methods From June to November 2010,cases information and fecal specimens were collected from guard-hospitals in Guiyang regions,who had caught the acute-gastroenteritis.Noroviruses in specimens were detected by a real-time reverse transcription polymerase chain reaction(real-time RT-PCR),and then partial genotyped norovirus-positive clinical samples (in random) were cloned and sequenced in VP1 gene code.Furthermore,the gene sequences were compared with the published variants at home and abroad of norovirus(GⅡ.4),including the phylogenetic analyses of genomes and variation of amino acids within individual sites.Results Those 267 specimens were GⅡ-norovirus-positive(62.68％) in 426 clinical samples.There were nine GⅡ.4-norovirus-positive VP1 gene-sequences available,and two subtype-norovirus variants (GⅡ.4 2008a and G Ⅱ.4 2008b variant) were epidemic in 2010,Guizhou province.The homology between and in subgroups were 95.90％-96.72％ and 99.45％-100％.Two amino acids within individual sites were apt to mutate.Conclusion Norovirus GⅡ genotype were predominant in summer and fall acute gastroenteritis in 2010 for Guiyang regions,and the variants were diversity.