The purpose of this study was to investigate the epidemiological characteristics and risk factors of influenza in Hainan province,to provide evidence to support influenza prevention and control efforts.Pathogen monitoring data of influenza-like illness(ILI)in six national sentinel hospitals in Hainan province from 2013 to 2021 were analyzed in SPSS 20.0 software.A total of 50 415 ILI cases were detected during the 2013-2021 season,of which 5 581 were positive for influenza viruses,with a positivity rate of 11.07％.The dominant strains were type B,type A(H1N1)pdm09 and type A(H3N2).The positivi-ty rate of influenza virus was highest in people 5-14 years of age(17.56％)and lowest in people 0-4 years of age(7.32％).Influenza activity showed both a summer peak and a winter-spring peak in the 2014-2016,2017-2018 and 2019-2020 sea-sons,and was concentrated in April to September,with a maximum peak of 53.64％,and in November to March of the next year,with a peak of 47.30％.The 2013-2014,2016-2017 and 2018-2019 seasons showed only a winter-spring peak concen-trated between October and March of the next year,with a maximum peak of 54.17％,but no obvious summer peak.The pre-dominant influenza viruses during the eight surveillance seasons varied among H1N1,H3N2 and type B.The positive detection rate of influenza virus steeply declined during the 2020-2021 season:the positive detection rate was only 0.25％,and no obvi-ous epidemic period was observed.The intensity of influenza epidemic varied among monitoring years,and the dominant strains changed rapidly in Hainan Province.People 5-14 years of age were the key population affected.Summer,winter and spring were the key periods for influenza prevention and control.Etiological surveillance of influenza should continue to be strength-ened,the roles of health education and publicity should be emphasized,and the dual measures of influenza vaccination and non-drug intervention should be actively promoted to decrease the occurrence of influenza.