Aim The study was to investigate the correlation between serum cystatin C （Cys C） and the degree of carotid stenosis in patients with transient ischemia attack or minor stroke. Methods A total of 229 patients with transient ischemic attack （TIA） or minor stroke were collected, and each of them received head and neck computed tomography angiography （CTA） inspection. All of the patients were divided into two groups: group with carotid stenosis and group without carotid stenosis. The group with carotid stenosis included 127 subjects of patients, which is divided into 4 subgroups: 44 subjects of mild carotid stenosis subgroup, 34 subjects of moderate carotid stenosis subgroup, 24 subjects of severe carotid stenosis subgroup, 12 subjects of oclussion subgroup Another 102 patients without carotid stenosis were selected as the control group. The levels of serum Cys C were detected by immunoturbidimetric assay, and the correlation between serum Cys C and the degree of carotid stenosis was analyzed. Results Serum Cys C level and homocysteine level were higher in carotid stenosis group than in without carotid stnosis group （P<0.01）. On spearman correlation analysis, carotid stenosis was correlated positively to age, serum Cys C, homocysteine （Hcy）, uric acid （UA）, hypertension and diabetes mellitus （P<0.05） The Logistic regression analysis showed that Cys C was not the independent risk factor for carotid stenosis. After the subjects of carotid stenosis group were divided into 4 subgroups according to the severity of carotid stenosis, serum Cys C levels were higher in severe carotid stenosis group than in without carotid stenosis group （P<0.05） The Cys C level of severe stenosis group was statistically and significantly different from mild stenosis group and moderate stenosis group （P<0.01, P<0.05）. The Logistic regression analysis showed that Cys C, triglyceride （TG）, hypertension were the independent risk factors for carotid with severe stenosis. Conclusion Serum Cys C level was positively correlated with carotid artery with severe stenosis in patients with transient ischemic attack or minor stroke, and was an independent risk factor for carotid artery with severe stenosis.