·AIM:To investigate a possible role for the angiotensin Ⅱ(Ang Ⅱ)and vascular endothelial growth factor(VEGF)in the development of retinal neovascularization.·METHODS:It was a random control experimental study.Forty seven-day-old C57BL/6J mice were divided into two groups randomly including normal control group and hyperoxia model group.Hyperoxia model group were exposed to 75% oxygen to establish a model of oxygen-induced retinopathy.Fluorescent angiography was used to assess the vascular pattern of retina.The proliferative neovascular response was quantified by counting the nuclei of new vessels extending from the retina into the vitreous in cross-sections.Ang II and VEGF protein levels in retinas were measured by Western blot.Significant differences between groups were evaluated by independent-samples t test and Pearson correlation analysis.Statictical difference was considered significant at a P value less than 0.05.·RESULTS:Fluorescent angiography presented increasing neovascular tufts with fluorescein leakage in hyperoxia model group compared to the normal control group.The number of endothelial cells of new vessels extending from retina to vitreous were increased significantly in hyperoxia model group(43.23±2.57)as compared with normal control group(1.37±0.93)(P=0.00).The expression of Ang II protein in retinas were increased significantly in hyperoxia model group(0.365±0.004)compared with normal control group(0.035±0.003)(P=0.00).The expression of VEGF protein in retinas were increased significantly in hyperoxia model group(0.372±0.004)compared with normal control group(0.049±0.007)(P=0.00).·CONCLUSION:There is specific relation between Ang II and VEGF in angiogenesis promoting effect.Ang II participate in the occurrence and development of retinal neovascularization via the upregulation the expression of VEGF.·