Abstract: Objective To analyze the clinical characteristics of children with Mycoplasma pneumoniae pneumonia （MPP） who progress into plastic bronchitis （PB） and identify the associated risk factors. Methods A total of 387 children diagnosed with MPP who underwent bronchoscopy were included in the study. They were divided into the MPP progressing into PB group and the MPP group based on the presence of plastic bronchial casts observed under microscopy. Clinical characteristics between two groups were compared, and the risk factors of the progression into PB were analyzed. Results The imaging findings, particularly from chest CT scans, revealed a higher incidence of atelectasis, lung necrosis, massive pleural effusion, bronchial stenosis or bronchial occlusion in the MPP progressing to PB group. Similarly, the occurrence of mixed infections, the levels of neutrophil percentage, lymphocyte percentage, neutrophil-to-lymphocyte ratio （NLR）, procalcitonin, C-reactive protein and lactate dehydrogenase （LDH） in the MPP progressing into PB group were significantly higher than those in the MPP group （all P < 0.05）. Multivariate logistic regression analysis demonstrated that NLR >3.15 ng/L OR （95% CI） =2.084 （1.155, 3.759）, LDH levels >408.5 U/L OR （95% CI） =3.469 （1.797, 6.696）, imaging changes OR （95% CI） =2.707 （1.241, 5.907）, and mixed infections OR （95% CI） =4.517 （2.201, 9.271） were the independent risk factors of MPP progressing into PB. Conclusions Characteristic imaging changes, mixed infections, and elevated levels of LDH and NLR are the independent risk factors for the progression of MPP into PB. Early identification of these factors by clinicians can enable prompt intervention.