Objective Through the investigation and disposal of the epidemic,the causes of the outbreak were analyzed. Methods In the school where the epidemic occurred,field epidemiological investigation was carried out,and the anal swabs of some patients were collected for norovirus nucleic acid detection. Results A total of 14 students suffered from the disease,and 6 anal swab samples were positive for norovirus GⅡnucleic acid.Case comparison analysis showed that there were statistically significant differences in the norovirus infection rates of whether vomit were within 1 m around the students (χ²=11.67,P＜0.05),and in the norovirus infection rate of whether there were norovirus patients around the students (χ²=7.47,P＜0.05). Conclusion This aggregative epidemic was caused by norovirus infection,and the spread of the epidemic may be mainly caused by close-up droplets and inhalation of aerosols containing vomitus.