Objective To analyze the epidemic situation of seasonal H1N1 influenza in Jinnan District of Tianjin from 2013 to 2018, and provide evidence for scientific prevention and control of influenza. Methods The Xianshuigu Hospital was selected as a monitoring sentinel hospital to collect throat swab specimens from children aged 0-14 years (ILI) from April 1, 2013 to March 31, 2018. Real-time quantitative RT-PCR was used. The seasonal influenza A H1N1 influenza virus nucleic acid was detected and analyzed statistically from April 1 to March 31 of the following year. Results The ILI throat swab specimens collected during the five monitoring cycles were 588, 601, 609, 591 and 583, respectively. The positive rates of seasonal influenza A H1N1 influenza viruses were 9.69%, 0,7.39%, 10.15% and 12.35%, respectively,the difference was statistically significant(P< 0.05). There are 4 seasonal influenza A H1N1 influenza epidemics in the 5 monitoring cycles, from December 2013 to January 2014, January to March 2016, February to March 2017, and January 2018. In February, the number of positive cases from March 2014 to December 2015 was zero. According to the age, the age groups were 0~2 years old, 3~5 years old, 6~8 years old, 9~11 years old and 12~14 years old. The positive rates were 3.15%, 9.98%, 11.08%, 8.52% and 5.98% respectively, the positive rate between each age group was compared, the difference was not statistically significant (P>0.05). There was no significant difference in the positive rate of seasonal H1N1 flu among different gender groups (P>0.05).Conclusion The seasonal influenza A (H1N1) virus is characterized by seasonal epidemic. The epidemic period is generally in winter and spring, and the peak period is around January. The number of positive cases in children aged 3 to 8 years old is the most susceptible. In order to better prevent and control the flu and grasp the fashion trends in a timely manner, it is still necessary to strengthen monitoring.