Aim To investigate the effect of Procyanidins on vascular endothelial cell in diabetic rats and discuss the possible mechanism. Methods Male SD rats were injected streptozotocin （ STZ， 30 mg/k g ） by tail intravenous for establishing the type I diabetes animal model，randomly divided into diabetes model group，50 mg/kg procyanidins treatment group and 100 mg/kg procyanidins treatment group，and other 8 healthy male SD rats were included into the control group. The rats took medicine by irrigation stomach for 12 weeks,rat fasting blood glucose was detected with glucose meter and special in-situ；serum ET-1 and PGI2 level were detected with radiation immunity analyzer；MDA and SOD in vascular endothelial cell were detected by the methods of ELISA Caspase-3 ,Bax and Bcl-2 in vascular endothelial cell were detected by the conventional immunohistochemical treatment and dyeing methods；vascular endothelial cell microscopic image was observed and collected with being future-proof imaging analysis system （× 400） at high magnification；Caspase-3 ,Bax and Bcl-2 in vascular endothelial cell were analysed by mean-density using the microscope Image analysis software Image - Pro Plus 6.0 in yellow. Results Compared with the normal control group,in Diabetes model rats,rat fasting blood glucose level increased， serum ET-1 level increased and PGI2 level reduced （P< 0.01）,MDA in vascular endothelial cell increased（P< 0.01）,SOD in vascular endothelial cell reduced（P< 0.01）,Caspase-3 and Bax in vascular endothelial cell increased（P< 0.01） Bcl-2 and Bcl-2/Bax in vascular endothelial cell reduced（P< 0.01）In 50 mg/kg procyanidins treatment group and 100 mg/kg procyanidins treatment group,rat fasting blood glucose level decreased （P< 0.05，P< 0.01），serum ET-1 level reduced and PGI2 level increased（P< 0.01）,MDA in vascular endothelial cell reduced （P< 0.01）,SOD in vascular endothelial cell increased （P< 0.05，P< 0.01）,Caspase-3 and Bax in vascular endothelial cell reduced （P< 0.01） Bcl-2 and Bcl-2/Bax in vascular endothelial cell increased （P< 0.01）. Conclusion Procyanidins has protective effect on diabetic rats vascular endothelial cell secretion function and oxidative damage,meanwhile can inhibit Caspase-3 and Bax ,induce Bcl-2 and Bcl-2/Bax of diabetic rat vascular endothelial cell.