Objective To evaluate the clinical value of high-frequency color doppler ultrasound in diagnosis of common carotid artery vasculopathy of diabetes mellitus. Methods High-frequency color doppler ultrasound was used to detect the intima-media thickness (IMT), inner diameter(CCAD), resistent index (RI) and atherosclerotic plaque of common carotid artery in 40 patients with diabetes, and then compared with 35 normal cases. Results IMT,CCAD and RI as well as incidence of atherosclerotic plaque of common carotid artery in diabetics were signifi-cantly higher than that in the control group(P < 0.05). Conclusion High-frequency color doppler ultrasound can di-rectly show the degree of carotid lesion and atherosclerotic plaque, and is of practical value and a guide in diagnosing atherosclerosis and preventing brain embolism in diabetics.