G9P[8] rotavirus A (RVA) has been identified as the predominant genotype circulating in Yunnan, China. To elucidate the molecular characteristics of its genetic composition at the whole-genome level, the genomes of 12 strains isolated from paediatric patients with diarrhoea were fully sequenced and characterized. Eleven of the 12 strains were genotyped as G9-P[8]-I1-R1-C1-M1-A1-N1-T1-E1-H1, which is closely related to the Wa-like genotype 1 constellation. In contrast, one strain was genotyped as G9-P[8]-I1-R1-C1-M1-A1-N2-T1-E1-H1, with the NSP2 gene characterized as a DS-1 like genotype. Bayesian phylogenetic analysis indicated that G9 strains had emerged in 1932 with an estimated average evolutionary rate of 1.63×10-3 substitutions/site/year. Considering the high prevalence and fast evolutionary rate of G9P[8] rotaviruses, our results suggest that G9P[8] RVA should be strictly monitored in China.