Objective To investigate positive picobirnaviruses(PVBs)infection and its association with unex-plained diarrhea in children. Methods From January to December 2015,the Clinical Microbiology Testing Center of Xuzhou Central Hospital as the sampling location,7 PVB reverse transcription - polymerase chain reaction(RT - PCR)- positive fecal samples with diarrhea were collected from children under 6 years old and 4 samples from healthy chil-dren were obtained and all the samples were analyzed by viral metagenomics to investigate the relationship between PVBs and diarrhea in children. Phylogenetic analysis of RdRp in the isolated PVB sequences was carried out to clarify the relationship between PVB classification and diarrhea. Results All the 7 diarrhea feces contained high titers of PVB sequences,while 3 of the controls were negative,and 1 with low titers of PVB. RdRp analysis was carried out on the iso-lated PVB sequences,which displayed that 7 RdRp sequences caming from 7 fecal samples separately,so named ChXz- 1 to ChXz - 7 respectively. Phylogenetic analysis based on the predicted amino acid sequences of RdRp from this study and whole RdRp sequences available in the GenBank database indicated that the 7 RdRp sequences belonged to 3 genogroups,in which ChXz - 1,ChXz - 2,ChXz - 3 belonging to genogroup Ⅰ,ChXz - 4,ChXz - 5,ChXz - 7 belong-ing to genogroup Ⅱ,and ChXz - 6 belonging to genogroup Ⅲ. Conclusions PVBs might be the cause of diarrhea in children in this study,and all the 3 different PVBs may lead to diarrhea.