Abstract： Objective:To analyze the changes of common pathogens of viral diarrhea in children during the COVID-19 epidemic.Methods:A retrospective analysis was performed on children with acute diarrhea treated in Children’s Hospital affiliated to Zhejiang University School of Medicine from 2019 April to 2019 December(before COVID-19, n=407)and 2020 April to 2020 December (during COVID-19, n=645). Children were further divided into 1-6 months, >6 months-2 years, >2-5 years age groups. Detection rates of norovirus GI (NOVI), norovirus GⅡ (NOVⅡ), rotavirus A (ROVA), rotavirus C (ROVC), intestinal adenovirus (EADV), sapovirus (SAV) and astrovirus (ASV) in different age groups and seasons before and during COVID-19 were compared by χ2 or Fisher exact test. Results:The total detection rates of diarrhea-causing viruses among age groups were significantly higher before COVID-19 than those during COVID-19( χ2=8.43, 38.22 and 9.23, all P<0.05). The detection rates of NOVⅡ and EADV in infants aged 1-6 months and >6 months-2 years were decreased during the period of COVID-19 epidemic( χNOVⅡ2 =36.87 and 17.77, both P<0.001, χEADV2 =9.08, P=0.014 and 0.003); the detection rates of NOVⅡ in children aged 2-5 years was decreased during the period of COVID-19 epidemic( χ2=3.96, P=0.047); the detection rates of other diarrhea-causing viruses were not decreased during the period of COVID-19 epidemic(all P>0.05). The detection rates of diarrhea-causing viruses among 4-6 months, 7-9 months and 10-12 months were higher during the period of COVID-19 epidemic( χ2=11.62, 65.41 and 27.80, all P<0.001). Conclusion:After the outbreak of COVID-19, the detection rate of common pathogens of viral diarrhea in children is decreased, especially NOVⅡ and EADV, which may be related to the measures in response to major public health events in Zhejiang Province.