BACKGROUND: Bronchopulmonary dysplasia (BPD) is prevalent and severe diseases in preterm infants, characterized by abnormal lung development. This study aims to investigate the therapeutic potential of proline betaine, a natural alkaloid recognized for its vasculo-protective and anti-inflammatory properties, in BPD model. METHODS: Network pharmacology was utilized to predict the targets of proline betaine and BPD-related genes (BPD-RGs). In vitro, HUVECs were treated with proline betaine to evaluate its effects on proliferation and angiogenesis. In vivo, a hyperoxia-induced BPD rat model (85 % oxygen, first day to 14th day) was used to evaluate the effects of proline betaine on pulmonary injury, angiogenesis and fibrosis. RESULTS: We identified a total of 100 proline-betaine targets and 825 BPD-RGs, with 20 shared targets between them. These shared targets modulated inflammation, immune response, hypoxia, and vascular homeostasis, especially the vascular phenotype. In vitro, proline betaine significantly enhanced the activity, number of tubes, and capillary length of HUVECs. The pro-angiogenic effect of proline betaine on HUVECs was dose-dependent. The hyperoxia-induced BPD rat model corroborated these findings. In vivo, proline betaine increased the radial alveolar count and reduced the mean linear intercept and collagen content in the lung. Mechanistically, proline betaine upregulated VEGF and VEGFR2 expression as well as MEK/ERK pathway activity. Notably, blocking the VEGFR2 and MEK/ERK pathways made proline betaine less effective as a medicine. CONCLUSION: Proline betaine enhances angiogenesis and mitigates pulmonary injury through the MEK/ERK pathway. These findings suggest that proline betaine could serve as a novel therapeutic strategy for managing BPD in neonates.