One unusual human G3P[3] group A rotavirus (RVA) strain M2-102 was identified in stool sample collected from a child with diarrhea in Guangxi Province, China in 2014. It is well known that G3P[3] is a genotype commonly identified in feline and canine RVAs. However, the preliminary phylogenetic analyses of the VP7 and VP4 genes of strain M2-102 indicated that these two genes were closely related to bat RVA strain MYAS33 and simian strain RRV, respectively, whereas both clustered distantly to feline/canine-like RVA strains. In this study, full genome sequencing and molecular analyses were conducted to obtain the true origin of strain M2-102. It was revealed that strain RVA/Human-wt/CHN/M2-102/2014/G3P[3] exhibited a G3-P[3]-I3-R3-C3-M3-A9-N3-T3-E3-H6 genotype constellation for VP7-VP4-VP6-VP1-VP2-VP3-NSP1-NSP2-NSP3-NSP4-NSP5 genes. Phylogenetic analyses revealed that 5 genes (VP7, VP1, VP2, NSP2 and NSP3) from strain M2-102 were closely related to those of bat strain MYAS33 from Yunnan Province which was thought a true bat RVA strain rather than a virus transmitted between species, while another 5 genes (VP4, VP3, NSP1, NSP4 and NSP5) clustered closely with those of simian strain RRV, yet the VP6 gene was closely related to that of human G3P[9] strain AU-1 and AU-1-like RVAs. The epidemiological data indicated that the child infected with M2-102 came from a countryside village, located in Dong Autonomous County of Sanjiang (subtropical hilly wooded area), Liuzhou city in Guangxi Province which might provide natural environment for reassortment events occurring among animal and human RVAs. Therefore, the data suggest that human strain M2-102 might originate from multiple reassortment events among bat, simian and human AU-1-like RVAs, yet it is not clear whether the genomic backbone based on bat MYAS33 (5 genes) and simian RRV (5 genes) like rotaviruses had been obtained through reassortment before being transmitted to the human. This is the first report on whole genome analysis of human G3P[3] RVA from China.