Objective To analyze the distribution and clinical characteristics of gastrointestinal virus infection in infants with acute diarrhea.Methods Stool samples and clinical data were collected from 900 infants (≤5 years old) with acute diarrhea in outpatient department of Beilun District People' s Hospital during July 2012 and July 2013.Specimens were tested for 5 gastrointestinal virus including group A/B/C rotavirus (RV),adenovirus (AdV),astrovirus (AstV),sapovirus (SV) and norovirus (NV) by the multiplex PCR assay.Chi-square test was performed to compare the positive rates of virus infection among children with different genders and ages.Results Among 900 stool samples,369 were positive of gastrointestinal virus,of which 291 were positive for single virus and 78 for mixed virus.In single virus infection,NV was detected with the highest positive rate of 19.4％ (4.9％ for G Ⅰ and 14.6％ for G Ⅱ),followed by RV-A (8.2％),SV (2.9％),AstV (1.0％) and AdV (0.8％).RV-B and C type were not found.In 78 cases with mixed infections,RV-A plus NV infection was the most common one with a prevalent rate of 5.8％.The positive rate in age group ≤2 years old was 51.0％,which was significantly higher than that of age group ＞ 2-5 years old (22.1％,x2 =70.404,P ＜ 0.01).In 369 children with positive gastrointestinal virus,fever was present in 24.1％,and vomit in 35.2％ of children.Fever,vomit and fever plus vomit was more common symptoms in children with mixed infections (x2 =17.878,21.869 and 14.155,P ＜ 0.01).Conclusion NV and RV-A are the most common pathogens in infants with acute diarrhea in Beilun district,especially in children younger than 2 years old.