OBJECTIVE: To investigate the pro-angiogenic effects of paeoniflorin (PF) in a vascular insufficiency model of zebrafish and in human umbilical vein endothelial cells (HUVECs). METHODS: In vivo, the pro-angiogenic effects of PF were tested in a vascular insufficiency model in the Tg(fli-1:EGFP)y1 transgenic zebrafish. The 24 h post fertilization (hpf) embryos were pretreated with vascular endothelial growth factor (VEGF) receptor tyrosine kinase inhibitor II (VRI) for 3 h to establish the vascular insufficiency model and then post-treated with PF for 24 h. The formation of intersegmental vessels (ISVs) was observed with a fluorescence microscope. The mRNA expression of fms-like tyrosine kinase-1 (flt-1), kinase insert domain receptor (kdr), kinase insert domain receptor like (kdrl) and von Willebrand factor (vWF) were analyzed by real-time polymerase chain reaction (PCR). In vitro, the pro-angiogenic effects of PF were observed in HUVECs in which cell proliferation, migration and tube formation were assessed. RESULTS: PF (6.25-100 μmol/L) could rescue VRI-induced blood vessel loss in zebrafish and PF (25-100 μmol/L), thereby restoring the mRNA expressions of flt-1, kdr, kdrl and vWF, which were down-regulated by VRI treatment. In addition, PF (0.001-0.03 μmol/L) could promote the proliferation of HUVECs while PF stimulated HUVECs migration at 1.0-10 μmol/L and tube formation at 0.3 μmol/L. CONCLUSION: PF could promote angiogenesis in a vascular insufficiency model of zebrafish in vivo and in HUVECs in vitro.