Aim To investigate the value of magnetic resonance imaging (MRI) in the diagnosis of symptomatic carotid stenosis and atherosclerotic plaque characteristics. Methods A total of fifty patients with symptomatic carotid stenosis which was determined by digital subtraction angiography (DSA) underwent bilateral carotid MRI examination. Stenosis percentage and stenosis degree were confirmed by using North American Symptomatic Carotid Endarterectomy Trial (NASCET) standard. With DSA as the "gold standard", the results of MRI and DSA were compared to evaluate the sensitivity, specificity and accuracy of MRI in the diagnosis of different degree of carotid stenosis. The incidence rates of intraplaque hemorrhage (IPH) and rupture fibrous cap (RFC) were calculated in different degrees of carotid stenosis. Results With DSA results as the "gold standard", the sensitivity, specificity and accuracy of MRI detection were as follows:93.1%, 97.5% and 90.6% in mild stenosis, 84.2%, 94.9% and 79.1% in moderate stenosis, 100%, 97.5% and 97.5% in severe stenosis, 100%, 100% and 100% in occlusion. The consistency coefficient of MRI and DSA i.e. Kappa value was 0.863. The rates of IPH were 29.1%, 45.0% and 52.6% and the rates of RFC were 23.6%, 40.0% and 57.9% respectively in mild stenosis, moderate stenosis and severe stenosis. Conclusions MRI has a high diagnostic value for carotid atherosclerosis and is helpful for early diagnosis and early treatment of cerebrovascular disease. It can not only evaluate the degree of carotid stenosis, but also analyze the composition of plaque according to the signal characteristics.