It is well-known that Vascular Endothelial Growth Factor (VEGF) and Angiopoietin (Ang)-1 are important regulators of alveolar and pulmonary vascular development. This study investigated the expression of VEGF and Ang-1 in postnatal rats with hyperoxia-induced lung injury and its effect on pulmonary development. Forty-eight 3-day-old Sprague-Dawley rats were randomly divided into 2 groups and exposed to either hyperoxia (≥ 95%) or air. Real-time PCR and Western blotting were used to measure the mRNA and protein expression levels of VEGF and Ang-1 in pulmonary tissues. No significant differences in the expression levels of VEGF and Ang-1 protein or mRNA were noted between the control and hyperoxia groups on days 1 and 3 (P>0.05); however, an obvious significant difference was noted on day 7 (P<0.05). The mRNA expression levels of VEGF and Ang-1 were 0.722 ± 0.372 and 0.828 ± 0.462, respectively, in the control group and 0.239 ± 0.293 and 0.327 ± 0.184, respectively, in the hyperoxia group. The protein expression levels of VEGF and Ang-1 were 0.632 ± 0.289 and 0.573 ± 0.436, respectively, in the control group, 0.358 ± 0.128 and 0.204 ± 0.068, respectively, in the hyperoxia group. The pulmonary tissues of the hyperoxia group manifested dysplastic characteristics with alveolar simplification, a reduction in alveolar numbers, and retardation in microvascular development. Since VEGF and Ang-1 are important regulators of alveolar and pulmonary vascular development that are involved in the pathogenesis of lung injury and development, their expression profile may be helpful for studying the pathogenic mechanism of and treatment for bronchopulmonary dysplasia.