Objective: To investigate the epidemiological characteristics of respiratory syncytial virus (RSV) in hospitalized children in Ningbo City, so as to provide insights into developing prevention and control strategies for RSV. Methods: Basic information, clinical data and throat swab samples were collected from hospitalized children with respiratory infection in Ningbo University Affiliated Women and Children's Hospital from July 2019 to December 2023. Multiple fluorescence PCR-capillary electrophoresis was employed to detect nucleic acids of 11 non-bacterial respiratory pathogens. RSV detection in hospitalized children by time, gender and age was descriptively analyzed. Results: A total of 49 449 throat swab samples of hospitalized children with respiratory infections were detected. There were 4 310 samples positive for RSV, with a detection rate of 8.72%. The detection of positive specimens peaked from November to February in 2019 and 2020, from August to October in 2021, and from May to September in 2023. The RSV detection rate in boys was higher than that in girls (9.25% vs. 8.04%, P<0.05). The detection rate of RSV was highest in the children under 1 year of age (16.37%). The RSV detection rate tended to decrease with age (P<0.05). Among the specimens with positive RSV detection, 3 407 were positive for RSV alone (79.05%), while 903 were detected as mixed infections (20.95%). The non-bacterial pathogens with higher percentages of mixed detection were human rhinovirus, Mycoplasma pneumoniae and human parainfluenza virus. Conclusion Atypical seasonal epidemic of RSV infections appeared in 2021 and 2023 among hospitalized children in Ningbo City, with high detection rates in boys and children under 1 year of age, and a certain percentage of mixed infections.