Objective:To explore the pulmonary microbiome characteristics of adolescent mice model of bronchopulmonary dysplasia(BPD). Methods:Thirty-two C57BL/6J neonatal mice were divided into air female group,air male group,hyperoxic female group,and hyperoxic male group,with 8 mice in each group. The mice in the hyperoxic group were placed in the environment with FiO2>95% for 7 days immediately after birth,and the mice in the air group were placed in the same indoor air with FiO2=21%. All mice were then raised in indoor air environment until 6 weeks. The pathological changes of lung tissues were observed by hematoxylin-eosin staining(HE). The characteristics of pulmonary microbiome were analyzed by 16S rDNA sequencing. Results:The alveolation degree of lung tissue decreased in early hyperoxygen exposure group(P < 0.01). Two-factor ANOVA showed that radial alveolar count(RAC) had no significant difference between sex in mice(F=2.001,P > 0.05). The results of Anosim similarity analysis showed that there was statistical significance in pulmonary microbiome of male mice in the air group and the high oxygen group(r=0.906,P=0.03),while there was no statistical significance in the female mice(r=- 0.0938,P=0.722).Alpha diversity results showed that there was no statistical difference in the species richness of lung flora between the high oxygen group and the air group(P > 0.05),and in the analysis of Beta diversity,PCoA diagram showed that there were statistical differences in lung flora among the four groups(P < 0.05). LEfSe analysis showed that the abundance of Corynebacterium in the high oxygen group decreased and Staphylococcus increased. Conclusion:The lung microbiota of adolescent mice in the BPD model are disregulated,with a decrease in the abundance of Corynebacterium,and an increase in Staphylococcus,and the microbiota imbalance might be related to gender.