NLR is the ratio of the number of neutrophils to the number of lymphocytes,and its variation represents the balance between the inflammatory response and immune regulation in the organism.NLR levels can be used as one of the predictors of the severity of infection-related diseases in children,such as childhood sepsis,respiratory infectious diseases,febrile convulsions,and hand,foot,and mouth disease,as well as a predictor of organ damage in childhood rheumatologic diseases such as IgA vasculitis and Kawasaki disease.NLR is also associated with childhood tumors,obstructive sleep apnea hypoventilation syndrome in children,and neonatal intracranial hemorrhage and other diseases.The relationship between NLR and related diseases in children is de-scribed.