Abstract: OBJECTIVE To explore the distribution and epidemiological characteristics of pathogens causing acute respiratory tract infections (ARTI) in children of Hangzhou so as to provide guidance for clinical prevention, diagnosis and treatment. METHODS A total of 3186 children with ARTI who were treated in Hangzhou Children's Hospital from Aug. 2023 to Jul. 2024 were recruited as the research subjects. The 13 species of common respiratory tract pathogens were detected by fluorescence PCR-capillary electrophoresis, the positive rates of pathogens and seasonal prevalence were observed. RESULTS Totally 2394 children were detected with pathogens, 1945(81.24%) of whom had single infection, 449 (18.876%) had mixed infections, and the children who had dual infections were dominant, accounting for 16.92%. The positive rate of Mycoplasma pneumoniae was highest (29.00%), followed by human rhinovirus (HRV) (16.60%) and respiratory syncytial virus (RSV) (9.45%). RSV was dominant in the infant group (less than 1 year old), HRV was dominant in the child group (1 to 3 years old), and M. pneumoniae was dominant in the preschool group (3 to 6 years old) and the school age group (6 to 18 years old). The positive rate of M. pneumoniae was increased with the age, while the positive rates of human parainfluenza virus (HPIV), human metapneumovirus (HMPV) and RSV showed downward trends (P＜0.05). M. pneumoniae was highly prevent in September to November, and HRV was highly prevalent in April to June. The incidence of severe pneumonia was lower in the preschool group than in the infant group and the child group (P＜0.05), and the incidence of mixed infections was higher in the children with severe ARTI than in the children with common ARTI (P＜0.05). CONCLUSIONS The positive rates of pathogens causing ARTI are high among the children in Hangzhou City. There are differences in the predominant pathogens among the age groups, M. pneumoniae is the predominant pathogen during the preschool age, and RSV is the predominant pathogen during infancy. The children with dual infections of HRV plus M. pneumoniae are dominant among the children with mixed infections, which are associated with the occurrence of severe illness.