Objective To investigate the clinical efficacy of bronchoalveolar lavage with fiberoptic bronchoscopy combined with budesonide nebulization in the treatment of mycoplasma pneumoniae lobar pneumonia in children, and its effects on immune function and inflammatory responses.Methods A total of 82 children diagnosed with mycoplasma pneumoniae lobar pneumonia, admitted to Jiangning Hospital, Nanjing, from February 2020 to May 2024, were selected. They were randomly divided into a control and an observation group using a random number table method, with 41 cases each. The control group received budesonide nebulization therapy, while the observation group received bronchoalveolar lavage with fiberoptic bronchoscopy in addition to budesonide nebulization therapy. The clinical efficacy, symptom and sign resolution time, peripheral blood T lymphocyte subsets (CD3⁺, CD4⁺, CD4⁺/CD8⁺), serum IL-17, hs-CRP levels, and the occurrence of adverse reactions were compared between the two groups.Results After treatment, the observation group had a higher total effective rate than the control group (P < 0.05). The cough and rales resolution times were shorter in the observation group compared to the control group (P < 0.05). The changes in peripheral blood CD3⁺, CD4⁺, and CD4⁺/CD8⁺ levels before and after treatment were greater in the observation group than in the control group (P < 0.05). Additionally, the changes in serum IL-17 and hs-CRP levels before and after treatment were higher in the observation group than in the control group (P < 0.05). There was no significant difference in the incidence of adverse reactions between the two groups (P > 0.05).Conclusion Bronchoalveolar lavage with fiberoptic bronchoscopy combined with budesonide nebulization is highly effective in treating mycoplasma pneumoniae lobar pneumonia in children. It can significantly alleviate clinical symptoms, regulate immune function, reduce inflammatory responses, and has good safety.