Objective: To Explore the evaluation value of neutrophil to lymphocyte ratio in the prognosis of Mycoplasma pneumoniae pneumonia. Methods: A retrospective analysis was applied to 2375 hospitalized children with Mycoplasma pneumoniae pneumonia in our hospital from January 2019 to December 2023. According to the severity of the condition, the children were divided into SMPP group (N=125) and non SMPP group (N=2250), then sub-grouped into RMPP group (N=451) and non RMPP group (N=1924). The basic data and clinical information of all pediatric patients were collected to assess the prognostic value of NLR in SMPP and RMPP. Results: NLR was an independent predictor of SMPP (OR=1.188, 95% Cl 1.123-1.299, P=0.033). Compared with children with a low NLR, children with a high NLR had a higher incidence of SMPP (P<0.001). NLR was also an independent predictor of RMPP (OR=1.320, 95% Cl 1.145-1.432, P<0.001). Children with a high NLR were more likely to develop SMPP and RMPP and had higher ICU hospitalization rate, total fever duration, longer hospital stays, and higher hospitalization costs than those with a low NLR ( P<0.001). Conclusion: NLR can be used to independently predict the prognosis of MPP and provide guidance for early treatment of SMPP and RMPP.