Objective：To investigate sensitive biological indicators for early diagnosis of bronchopulmonary dysplasia（BPD）by testing the expressions of 5-lipoxygenase activating protein（FLAP），leukotriene C4 synthase（LTC4S）and cysteinyl leukotriene receptor 1（CysLTR1） in serum of premature infants with BPD. Methods：Patients of the newborn less than 37 weeks of gestational age and less than 2 500 g of birth weight from the First Affilated Hospital of NMU were divided into 3 groups based on completed hospitalization information after discharge：premature infants without pulmonary diseases（the control group，n=65），premature infants with neonatal respiratory distress syndrome（NRDS）but without BPD（the NRDS group，n=60）and premature infants with BPD（the BPD group，n=49）. Serum levels of FLAP，LTC4S，CysLTR1 of the premature infants were tested by using enzyme-linked immunosorbent assay（ELISA）respectively at 3，7 and 14 days after birth. Statistical analysis was performed by variance analysis，t-verification and chi-square test etc. to compare the concentrations of 3 groups at different time points. Results：Serum levels of FLAP and CysLTR1 of infants with BPD at 3 days after birth were statistically significantly higher than that of NRDS and controls（P < 0.05）. Serum levels of FLAP，LTC4S and CysLTR1 of infants with BPD at 7 days after birth were significantly higher than that of controls（P < 0.05）. Serum levels of FLAP and CysLTR1 of infants with BPD at 7 days after birth were significantly higher than that of NRDS（P < 0.05）. Serum level of LTC4S in infants with BPD at 14 days after birth was higher than that of controls（P < 0.05）. Conclusion：Levels of serum FLAP and CysLTR1 of 3 days after birth，levels of FLAP，CysLTR1 and LTC4S of 7 days after birth，and LTC4S level of 14 days after birth may be useful biomarkers for early diagnosis of BPD.