Objective To investigate the clinical value of transcranial color Doppler ultrasonography combined with carotid artery ultrasonography in the evaluation of cerebral arteriosclerosis in patients with diabetes mellitus. Methods 120 patients with diabetes mellitus and 120 cases who took health examination in hospital from March 2013 to February 2015 were included as the observation group and the control group. Transcranial color Doppler ultrasonography and carotid artery ultrasonography were applied in both group. The intima-media thickness (IMT), resistance index (RI) and pulsatility index (PI) of both groups were observed. According to IMT, The observation group were divided into thickening group (IMT≥1.0mm) and non-thickening group (IMT<1.0mm), the average blood flow velocity of left and right vertebral artery and basilar artery in each group were detected. Results IMT, RI and PI of carotid artery in the observation group were significantly higher (P<0.05) than in the control group. There were 23 cases with IMT≥1.0mm and 97 cases with IMT<1.0mm in the observation group. The average blood flow velocity of left and right vertebral artery and basilar artery in thethickening group were significantly slower (P<0.05) than in the non-thickening group and control group. Conclusion Transcranial color Doppler ultrasonography combined with carotid artery ultrasound can effectively assess the cerebral artery atherosclerosis in patients with diabetes, which is conducive to the prevention and treatment of cerebral vascular disease, it is worth promoting.