Abstract: Objective To analyze the detection results of serum immunoglobulin M(IgM)antibody of 9 pathogens of respiratory tract infection in children. Methods A total of 200 children with respiratory tract infection were selected as the research objects. Peripheral venous blood was collected on the day of hospital admission, and serum IgM antibody of 9 pathogens of respiratory tract infection was detected by indirect immunofluorescence method. Results Among 200 cases, pathogens were detected in 63 cases(31.50%), including 49 cases(77.78%)of one pathogen infection, 12 cases(19.05%)of mixed infection of two pathogens, and 2 cases(3.17%)of mixed infection of three pathogens. The most common pathogens were mycoplasma pneumoniae(MP)infection(42 cases)and influenza B virus(IFFBV)infection(10 cases). The positive rate of pathogens in female children was 47.56%, which was significantly higher than 20.34% in male children(P<0.05). The positive rates of pathogens in the pre-school group and the school-age group were significantly higher than those in the infant group and the young children group(P<0.05). The positive rate of pathogens in the spring group was 58.93%, which was significantly higher than 22.92% in the summer group, 22.00% in the autumn group and 17.39% in the winter group(P<0.05). Conclusion MP and IFFBV are the main pathogens of respiratory tract infection in children, and the prevalence of - respiratory pathogens is closely related to children's gender, age and the season.