Abstract: Objective: To provide scientific basis for the prevention and control of influenza by analyzing the surveillance data and epidemic situation of influenza in Suzhou city from 2009 to 2012.Methods: The Real-Time PCR technology was used to detect the specificity nucleic acid of influenza virus in collected influenza-like cases or throat swab specimens from patients with influenza.Results: A total of 1 672 specimens were tested,among which 214 were found to have positive specificity nucleic acid of influenza virus,with a total positive rate of 12.8%.Among the 287 samples detected in 2009,positive specificity nucleic acid of influenza virus was found in 155 of them(54.0%);among the 729 samples detected in 2010,positive specificity nucleic acid of influenza virus was found in 39 of them(5.3%);among the 319 samples detected in 2011,positive specificity nucleic acid of influenza virus was found in 4 of them(1.3%);among the 337 samples detected in 2012,positive specificity nucleic acid of influenza virus was found in 16 of them(4.7%).The 214 patients with positive influenza virus nucleic acid were mainly concentrated at the age group of 0 to 10,followed by the age group of 20.The ratio of male and female was 1.2:1,and the positive rate of male and female was 12.0% and 13.9%,respectively;the difference was not statistically significant(P >0.05).Conclusions: The positive rate of specific nucleic acid of influenza virus declines from 2009 to 2011 year by year;but the positive rate in 2012 is higher than that in 2011,so monitoring,prevention and control work still needs to be strengthened.Children and adolescents are the high risk population for influenza with no gender differences.