Objective To analyze the etiology of respiratory tract infection in Yuancheng District of Heyuan City ,which was in different ages and seasons,and to provide guidance of clinical drug usage．Methods Cases of 2 468 hospitalized children with respiratory tract infection from March 2020 to February 2022 were analyzed．The secretion from pharynx was collected and sent to Guangzhou Da’an Clinical Examination Center for six respiratory nucleic acid tests and then the results were analyzed,including Streptococcus pneumoniae（Sp）,respiratory syncytial virus（RSV）,Moraxella catarrhalis（MC）,Haemophilus influenzae（Hi）,Mycoplasma pneumonia（MP）,adenovirus（ADV）．Results The positive rate of 2 468 hospitalized children with respiratory tract infection was 52.8%,of which the highest was RSV,followed by Sp,Hi,MC,MP,ADV．Meanwhile the mixed infection rate was second to RSV．RSV infection was the main infection in infant group and early-aged children group,while in preschool group and school-aged group,Sp infection was the main infection．There were many mixed infection of pathogen,and one bacteria combined with one virus was more common．Respiratory tract infection had high incidence in autumn and winter in Yuancheng District of Heyuan City,RSV was the major pathogen．Conclusions Autumn and winter were the seasons with high respiratory tract infection incidence in Yuancheng District of Heyuan City,and RSV was the main pathogen in these two seasons．RSV was also the main pathogen of infant group infection．But with the increase of children’s age,bacterial infection became the main reason of respiratory tract diseases．Mixed infection accounts for a high proportion in all age groups,which should be valued in clinical diagnosis and treatment．