Background <p>This study aimed to analyze the clinical characteristics and identify predictive factors associated with small segment molded sputum plugs in pediatric patients with Mycoplasma pneumoniae pneumonia (MPP).</p> Methods <p>A retrospective analysis was performed on the clinical data of pediatric patients diagnosed with MPP who underwent bronchoscopy at our hospital between December 2021 and April 2024. Multivariate logistic regression was employed to determine independent predictors of small segment molded sputum plug formation.</p> Results <p>Among 116 pediatric patients with MPP who met the study criteria, 48 (41.38%) were found to have small segment molded sputum plugs, while 68 (58.62%) did not. Patients with a history of recurrent respiratory infections, diminished breath sounds, and radiological evidence of atelectasis were significantly more likely to develop molded sputum plugs (<i>P</i> &lt; 0.05). Furthermore, the group with small segment molded sputum plugs exhibited a longer duration of fever <i>(P</i> = 0.025) and elevated levels of procalcitonin (PCT; <i>P</i> = 0.024), alanine aminotransferase (ALT; <i>P</i> = 0.048) and prothrombin time (PT; <i>P</i> = 0.021). Multivariate logistic regression analysis identified a history of recurrent respiratory infections and diminished breath sounds as independent predictors for the development of small segment molded sputum plugs.</p> Conclusions <p>A history of recurrent respiratory infections and diminished breath sounds emerged as independent predictors of small segment molded sputum plugs in pediatric MPP. These findings highlight the importance of considering these clinical features during the evaluation of MPP patients to inform diagnostic and therapeutic decision-making. Future studies are warranted to investigate the potential benefits of early detection and intervention on clinical outcomes in pediatric MPP.</p>