Abstract: Objective To understand the distribution of norovirus outbreaks and associated factors in Chengdu,and to provide scientific evidence for future work.Methods A total of 74 norovirus outbreaks were included and analyzed.Chi-square test and binary logistic regression were employed.Results Totally 779 cases were included into analysis.There was an average of 10.53 cases for each outbreak which lasted for 38.08 hours.The peak period of incidence ranged from November to December.Most outbreakCounties in the first-level economic region had the most epidemics,and kindergartens and primary schools were the high-risk places.The first case's vomiting at school(OR=3.27),epidemic information from other resources(OR =5.47) and primary school (OR=5.69) were the influential factors of a stronger epidemic(P<0.05).No significant factors were found associated with the lasting time of every epidemic.Conclusion To prevent norovirus infection,it is advised that prevention training should be conducted to increase the awareness and ability to identify cases early and dispose the fomites appropriately.Health education as well as health management should also be enhanced.