Objective To explore epidemiological characteristics of Norovirus enteritis outbreak in collective unit, and provide scientific basis for preventing and controlling outbreak. Methods We collected all cases of diarrhea information from a school hospital during March 1 to March 15th in 2017.The scene and a retrospective epidemiological investigation method was used, combined with the laboratory tests of biological and environmental samples. Results The epidemic lasted 15 days, with 110 cases and attack rate had reached 1.06%. After testing 180 biological samples from patients and canteen staff, Norovirus nucleic acid tests were positive in 29 copies, including 8 students with positive rate of 42.11% (8/19), 21 canteen staff with positive rate of 13.04% (21/161). Conclusion The latent infection of norovirus in canteen workers is the main cause of the outbreak.