Abstract: Objective To investigate the clinical characteristic and risk factor for sporadic NVs infections.Methods To assess the medical importance of NVs infection,the clinical characteristics of children infected with Norovirus(NVs)were compared with those found in patients infected with rotavirus.And all: case-control study was performed with the objective of identifying the risk factors for sporadic NVs infection.Results From 102 cases positive for NVs,82(80.3%)were associated with vomiting,54(52.9%)fever,24(23.5%)dehydration,8(7.8%)abdominal pains,and 48(47.0%)with the first symptom of diarrhea.Consumption of crude or cold foods was a risk factor for sporadic NVs infection,contacting with gastroenteritis was a doubtful risk factor and to trim the nail was the protective factor.Conclusion NVs diarrhea clinical severity was equal to that in rotavirus.Efforts to prevent contamination of the potential vehicle(food or water)and personto-person NVs transmission and keep good personal hygiene could prevent the occurrence and spread of NVs infection.