Objective：To study the difference of respiratory pathogen distribution in children with Tracheobronchomalacia （TBM） complicated pneumonia and children with simple pneumonia. Methods：Retrospectively analyze medical records and bronchoalveolar lavage fluid（BALF） specimen data of two groups，children with tracheobronchomalacia complicated pneumonia which named TBM group and children with simple pneumonia which named NTBM group，from January 2012 to December 2016 in Children’s Hospital of Chongqing Medical University，with 337 cases in each group. According to their age，they were divided into infant group（aged 0 days to 1 year） and young children group（aged 1 to 3 years）. According to the severity of pneumonia，they were divided into severe pneumonia group and non-severe pneumonia group. Then data was compared in groups. Results：①As a whole，in TBM group and NTBM group，the total bacteria positive rate were 54.90% and 45.99%，and with significant difference（P=0.021）. The tops four bacteria were Streptococcus pneumoniae，Escherichia coli，Kleb－siella pneumoniae and Hemophilus parainfluenzae. The positive rate of Escherichia coli were 12.17% and 4.75%，and respec－tively with significant difference（P=0.001） among two groups. ②Considering the non-severe pneumonia group，in TBM group and NTBM group，the positive rate of bacteria were 57.75% and 47.62%，the positive rate of Escherichia coli were 11.24% and 4.40%，and the positive rate of Klebsiella pneumoniae were 10.46% and 4.40%，respectively with significant difference（P=0.019，P=0.003，P=0.007） among two groups. As to bacterial type in infant group，the Escherichia coli ranked first in TBM group and the Strep－tococcus pneumonia ranked first in NTBM group. The Escherichia coli postive rate of two groups were 13.89% and 5.31% re－spectively，with significant difference（P=0.001）. ③Respiratory syncytial virus（RVS） ranked first in TBM group and NTBM group，with no significant difference（P=0.502）. There was no significant difference in total virus positive rate and Mycoplasma pneumonia positive rate between the two groups（P=0.361，P=0.055）. Chlamydia pneumonia positive rate was 0. Conclusion：①Difference in bacterial distribution existed between TBM complicated pneumonia and simple pneumonia. The distribution was the most in Escherichia coli，which ranked first in infant particularly. ②In the non-severe pneumonia group，bacterial infection rate of children with TBM complicated pneumonia was higher than that of children with simple pneumonia，among which the Escherichia coli infection rate was significantly higher. ③In term of the distribution of virus and Mycoplasma pneumonia，there was no significant difference between children with TBM complicated pneumonia and children with simple pneumonia. Chlamydia pneumonia infection was not found in the study.