Abstract：Objective：To observe the clinical effect of modified Yiqi Huoxue prescription combined with western medicine for type 2 diabetes mellitus(T2DM). Methods： A total of 300 cases of T2DM patients were selected and divided into the control group and the observation group randomly，with 150 cases in each group. The control group was treated with western medicine，and the observation group was additionally treated with modified Yiqi Huoxue prescription based on the treatment of the control group. Both groups were treated for four weeks. Before and after treatment，blood glucose indexes，kidney function indexes，total cholesterol(TC)，carotid intima-media thickness(IMT)，carotid peak systolic blood flow velocity(PSV) and Chinese medicine syndrome scores were compared between the two groups. Adverse reactions in the two groups were recorded. Results： After treatment， levels of fasting blood glucose(FBG)， 2- hour postprandial blood glucose(P2hBG)， serum creatinine(SCr)，uric acid(UA) and TC in the two groups were decreased when compared with those before treatment (P＜0.05)， and the above five levels in the observation group were lower than those in the control group(P＜0.05). After treatment， IMT and PSV of carotid in the two groups were decreased when compared with those before treatment(P＜ 0.05)， and IMT and PSV of carotid in the observation group were smaller than those in the control group(P＜0.05). After treatment， Chinese medicine syndrome scores in the two groups were decreased when compared with those before treatment(P＜0.05)，and Chinese medicine syndrome score in the observation group was lower than that in the control group (P＜0.05). During treatment， there was no severe adverse reaction in the two groups. Conclusion： Modified Yiqi Huoxue prescription combined with western medicine for T2DM can effectively control blood glucose and TC， protect the kidney function and vascular function，and relieve clinical symptoms with high safety.