Objective:Through analyzing pulmonary function and clinical characteristics of preterm infants with bronchopulmonary dysplasia (BPD) from 0 to 6 months, the characteristics of pulmonary function in infants with BPD were investigated.Methods:A retrospective study was conducted on 85 infants hospitalized in the Department of Neonatology of the First Affiliated Hospital of Shantou University Medical College from December 2015 to December 2017, including 25 preterm infants with BPD (BPD group), 30 preterm infants without BPD (preterm control group), and 30 term infants without respiratory diseases (full-term control group), respectively.Pulmonary function were tested in preterm infants at 37 to 41 weeks of corrected age as well as at 6 months of corrected age, and full-term infants at 3 days to 1 week after birth as well as at 6 months old.The outcomes of respiratory system diseases at 6 months of corrected age in two groups of preterm infants were followed up.Results:(1) While preterm infants at 37 to 41 weeks of corrected age and full-term infants at 3 days to 1 week after birth, time to peak tidal expiratory flow/expiratory time(TPTEF/TE)and volume to peak tidal expiratory flow/exhaled volume(VPTEF/VE) of BPD group were lower than those of the other two groups ( P<0.05), while the differences between preterm control group and full-term control group is not significant.VPTEF, peak expiratory flow (PEF), tidal expiratory flow when 75% of tidal volume reminds in the lung (TEF75%), TEF50%, TEF25% in BPD group and preterm control group were lower than those in the full-term group ( P<0.05). The differences between BPD group and preterm control group were not significant ( P>0.05). The BPD group had significantly lower TPTEF/TE, VPTEF/VE and ratio of tidal expiratory flow and tidal inspiratory flow when 50% of tidal volume reminds in the lung (TEF50%/TIF50%) and higher VPTEF, PEF, TEF25% at 6 months of corrected age than those at 37 to 41 weeks of corrected age ( P<0.05). While at 6 months of corrected age, the BPD group had higher PEF than that in the preterm control group ( P<0.05). There was no statistically significant difference between that in the occurrence of lower respiratory tract infections (43.3% vs.16.7%), wheezing (21.7% vs.8.3%), rehospitalization (39.1% vs.16.7%) between BPD group and preterm control group within 6 months of corrected age ( P>0.05). Conclusion:Infants with BPD had small airway obstruction at 37 to 41 weeks of corrected age and may not improve significantly at 6 months of corrected age.