Objective： Study on the protective effects and mechanisms of flavonoids from Mung bean hull on human umbilical vein endothelial cells（HUVEC） following oxidative injury caused by hydrogen peroxide（H2O2）. Method： Flavonoids were extracted from Mung bean hull with 70% ethanol and its bioactive components were quantified by HPLC. The HUVEC cells oxidative stress damage model was established by using H2O2. Experiments were divided into normal control group， H2O2 injury group， VitC control group， and low， medium， high flavonoids protective groups（20，60，80 μg/mL）. The proliferation was determined by the MTT assay. SOD， GSH-Px， LDH activities， GSH， MDA content in HUVEC cells and culture medium were assayed using biochemical colorimetry. Result： H2O2 could decrease the activity of endothelial cells in a dose-dependent manner， and induce apoptosis. Among them， compared with normal control group， cell proliferation was obviously inhibited after 24 h incubation with 1 000 μmol/L H2O2. However， In all dose groups of flavonoids from mung bean hull， the activities of superoxide dismutase（SOD）， glutathione peroxidase（GSH-Px） and glutathione （GSH） content were significantly increased （P<0.05）. The content of malondialdehyde （MDA） was significantly decreased （P<0.05）. The lactate dehydrogenase（LDH） activity was significantly decreased in cells and was significantly reduced in cell culture medium （P<0.05）. Conclusion： Flavonoids from mung bean hull can decrease the apoptosis of HUVEC injured by H2O2， its mechanism may be related to inhibiting lipid peroxidation damage cells， effectively improving the cells antioxidant enzyme activity， eliminating free radicals.