Objective To explore the lung function characteristics of routine ventilation and pulse oscillation in children with lobar pneumonia infected with Mycoplasma pneumoniae（MP）．Methods Ninety children with MP infected lobar pneumonia admitted to Guangzhou Women and Children's Medical Center from May 2022 to May 2023 were selected as the observation group,and 50 healthy children undergoing ventilation examination were selected as the control group．Based on the lesion,cases with multi lobar involvement were selected as the observation group A（10 cases）,cases with single lobar involvement were selected as the observation group B（80 cases）．All patients underwent routine ventilation and pulse oscillation received pulmonary function measurement,and the measurement results were observed．Based on this,the characteristics of lung function were analyzed．Results The results of routine ventilation lung function indicators in the observation group were lower than those in the control group,and the difference was statistically significant（P<0.05）．The measured/expected values of R5 and R20 in the observation group were higher than those in the control group,while the measured values of X5 were lower than those in the control group,with statistical significance（P<0.05）．There is a negative correlation between airway resistance indicators and lung function（P<0.05）．The measured/predicted values of vital capacity max（VCMAX）,peak expiratory flow（PEF）,forced vital capacity（FVC）75%,FVC50%,and FVC25% in the observation group were not with statistically significant difference．The measured/predicted values of FVC and FEV₁ in the observation group A were lower than those in the observation group B,and the difference was statistically significant（P<0.05）．There was no statistically significant difference in pulmonary function between the two groups of pediatric patients with pulse oscillation（P>0.05）．Among the 90 patients,12 had abnormal conventional ventilation．The measured/predicted values of VCMAX,FVC75%,and FVC50% before and after treatment were not significantly different．The measured/predicted values of FVC,FEV₁,PEF,and FVC25% before treatment were lower than those after treatment,and the difference was statistically significant（P<0.05）．Conclusions There is good correlation between conventional ventilation and pulse oscillation．Airway resistance has a reverse effect on VCMAX and FVC．MP infected lobar pneumonia is mainly characterized by impaired small airway ventilation function and increased airway resistance．