Objective：To explore the diagnostic value of serum tenascin C(TNC)in bronchopulmonary dysplasia(BPD)of the premature infants. Methods：Seventy-nine very low birth weight premature infants were enrolled from Department of Neonatology，the Affiliated Huai’an No.1 People’s Hospital of Nanjing Medical University from 2018 to 2020. According to the 2018 NICHD diagnostic criteria，they were divided into the non -BPD group(n=48)and the BPD group(n=31). ELISA was used to detect serum TNC level； Multivariate logistic regression was conducted to analyze the independent risk factors of BPD；The correlation between serum TNC level and the severity of BPD was analyzed by Kendall correlation；Receiver operating characteristic(ROC)curve of TNC for diagnosis of BPD was made. Results：①The serum TNC level of preterm infants was statistically different between the non-BPD group and the BPD group[(95.03±19.73)ng/mL vs.(125.40±19.34)ng/mL，P ＜ 0.001]，and there was statistical difference between different levels of BPD groups(P ＜ 0.001). ②The independent risk factors for BPD in premature infants included birth weigh，high concentration oxygen inhalation time and serum TNC level(P ＜ 0.05). ③Serum TNC level was positively correlated with the severity of BPD(r =0.617， P ＜ 0.001). ④The area under the curve for the diagnosis of BPD by serum TNC was 0.881(P ＜ 0.001)，the sensitivity was 96.8%， and the specificity was 66.7%. Conclusion：Serum TNC level increases in BPD，and the diagnostic sensitivity and specificity is high， which can be used as one of the biomarkers for diagnosis of premature BPD.