Abstract： Objective To explore the efficacy observation and serological study of xiao'er qingyan mixture(716 mixture)in the treatment of respiratory tract infection caused by respiratory syncytial virus.Methods 80 children with respiratory tract infection caused by respiratory syncytial virus admitted to Jiangxi Children's Hospital from January 2023 to September 2023 were selected as the research subjects.According to the random control table,they were divided into observation group(40 cases)and control group(40 cases).The control group was treated with nebulized inhalation combined with intravenous infusion,while the observation group was given administration of xiao'er qingyan mixture(716 mixture)on the basis of the control group.Compare the clinical efficacy,inflammatory factors[interleukin-6(IL-6),interleukin-10(IL-10),C-reactive protein(CRP),serum amyloid A(SAA),tumor necrosis factor-α(TNF-α)],immune function levels(CD4+、CD8+、CD4+/CD8+),recovery situation and adverse reactions before and after treatment between the two groups.Results The total effective rate of treatment in observation group was 95.00%,which was higher than 80.00%in control group(P<0.05).After treatment,the levels of IL-6,IL-10,CRP,SAA,TNF-α were decreased in the two groups,and the observation group had lower levels(P<0.05).The levels of CD4+and CD4+/CD8+in observation group after treatment were higher than those in control group while the level of CD8+was lower than that in control group(P<0.05).The observation group had shorter fever abatement time,cough relief time,asthma relief time and hospital stay(P<0.05).No adverse reactions occurred in the two groups during treatment.Conclusion Xiao'er qingyan mixture(716 mixture)can relieve the inflammatory symptoms,enhance the immune function,promote the recovery of children with respiratory syncytial virus infection,with good safety.