Abstract: Objective:To explore the effects of Yindan Xinnaotong soft capsule on the oxidative stress and vascular endothelial function in patients with type 2 diabetes mellitus complicated with coronary heart disease(CHD).Methods:A total of 150 patients with T2DM complicated with CHD were randomly divided into the observation group and the control group.The control group was treated with reducing blood glucose,reducing lipid,anti-coagulation,β-receptor blockers,nitrates and angiotensin converting enzyme inhibitor,and the observation group was additionally treated with Yindan Xinnaotong soft capsule by oral based on the control group for 12 weeks.The effects in two groups were evaluated after 12 weeks of treatment.Results:The levels of whole blood viscosity(high shear,middle shear and low shear),hematokrit,plasma viscosity and fibrinogen in observation group were significantly lower than those in control group(P<0.01).The levels of superoxide dismutase and malondialdehyde in observation group were significantly higher and lower than those in control group,respectively(P<0.01).The levels of endothelin,and the level of NO,non-endothelium-dependent vasodilation function induced by nitroglycerin and endothelium-dependent vasodilation function induced by blood flow in observation group were significantly lower and higher than those in control group,respectively(P<0.01).After treatment,the angina frequency,angina duration and nitroglycerin dosage in observation group were significantly lower than those in control group(P<0.01).Conclusions:Yindan Xinnaotong soft capsule in the treatment of T2DM complicated with CHD can effectively improve the hemorheology,alleviate the oxidative stress state,protect the vascular endothelial function and relieve the clinical symptoms,which is worthy of promotion in clinic.