Abstract: Objective To examine the characteristics and influence factors of influenza outbreak in Shaanxi province and to provide references for the prevention and control of influenza.Methods Data on influenza outbreaks from January 1,2006 to December 31,2013 were collected from public health emergence report information system and epidemiologic characteristics and influence factors of the outbreaks were analyzed.Results A total of 73 influenza outbreaks were reported in the province during the period. The reports of influenza outbreak concentrated from October of a year to February of the next year,accounting for 78.08%of all outbreaks.The influenza outbreaks were reported mainly in Guanzhong and Shaannan areas(63 outbreaks,86.30%).The most of the reported outbreaks(71,97.26%)occurred in schools and the prevalent influenza strains of the outbreaks were novel influenza A H1N1 and influenza B,accounting for 72.60%and 20.55%of the outbreaks.Based on the analyses for 64 school outbreaks,the duration of an influenza outbreak associated with the scale of the school,the time of taking control measures,and types of influenza virus(all P<0.05)and the intensity of an outbreak related to epidemic region,the scale of the school,the number of pupils in a class,the time of taking control measures and the pattern of class suspension(all P<0.05).Conclusion The influenza outbreaks were mainly local epidemic and occurred mainly in schools and during the period of November of a year to February of the next year in Shaanxi province from 2006 to 2013,suggesting implementation of preventive measures as soon as possible is most effective for the control of the outbreak.