Aim To explore the relationship between the feature of carotid atherosclerotic plaque and cerebral hemodynamic status by 16-slice spiral computed tomography (CT). Methods 42 cases with carotid atherosclerotic plaques tested by carotid ultra-sonography had CT perfusion (CTP) and CT angiography (CTA). The CT values (housefield value,HV) of the major plaque components were assessed. According to different CT values, plaques were defined as stable (including lipid core and fibrous tissue) or instable (calcification ). Then CTP was used to evaluate the cerebral hemodynamic status. Results Among 42 cases, 25 cases had instable plaques. Of which a lipid core was found in 10 cases and fibrous tissue in 15 cases. Hypo-perfusion status was occurred in 14 cases, while 70% in lipid core, and 47% in fibrous tissue, but none in calcification tissue. Conclusion Instable plaque is more relative with hypo-perfusion than stable plaque.