Abstract: OBJECTIVE To investigate the effects of Yindan Xinnaotong capsule on platelet activating factors, blood rheology and endothelial function in patients with type 2 diabetes mellitus. METHODS A total of 104 patients with type 2 diabetes mellitus were randomly arranged into the two groups, receiving glucose-lowing drug only(control group, 51 cases) or glucose-lowing drug plus with Yindan Xinnaotong capsule(treatment group, 53 cases) respectively. The therapeutic course for all were 12 weeks. The expression of membrane glycoprotein PAC-1 and CD62p, the parameters of blood rheology, NO and ET-1 were detected in 2 groups before and after treatment. RESULTS Compared with before treatment, the expression of platelet membrane glycoprotein PAC-1 and CD62p, the parameters of blood rheology and ET-1 were significantly lower (P<0.05), NO were significantly higher in the treatment group(P<0.05), meanwhile the changes of datas in the treatment group were more significantly than those in the control group(P<0.05). There was no significant differences of datas between before and after treatment in control group. CONCLUSION Yindan Xinnaotong capsule can decrease the platelet activation, blood viscosity, ET-1 and imcrease NO, and also improve the vascular endothelial function in patients with type 2 diabetes mellitus.