ObjectiveTo investigate and dispose an outbreak of seasonal influenza in hospital, so as to provide reference for the prevention and control of influenza outbreak in hospital.MethodsEight cases of influenzalike infection occurred in the department of neurosurgery at a hospital between July 29 and August 7, 2014, epidemiological investigation was conducted, throat swabs of infected persons were collected for laboratory detection.ResultsOf 8 infected persons, 6 were health care workers (HCWs) in department of neurosurgery, 1 was a family member of HCW, and 1 was a patient, the major symptoms of the infected persons were lowgrade fever, sore throat, and malaise, there were 67 patients and HCWs in this department, the attack rate of influenza was 11.94％, there was no similar infection in other departments of the hospital during the same period. The throat swabs from 6 infected HCWs were positive in influenza virus nucleic acid detection. Office for healthcareassociated  infection (HAI) management participated the investigation, after active isolation and antiviral treatment, the outbreak was effectively controlled. ConclusionThis HAI outbreak is a seasonal influenza H3 outbreak, ventilation and environmental disinfection in wards should be strengthened when central air conditioning is running, antiinfluenza vaccination among HCWs should be performed during the epidemic season of influenza,and surveillance should be strengthened to prevent influenza outbreak in hospital.