Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is the most common hereditary cerebral small vessel disease (SVD). This study aimed to use susceptibility weighted imaging and mapping (SWIM) at 7 Tesla to evaluate venous oxygen saturation (SvO2) and subcortical nuclear iron deposition and explore the correlation of these parameters with the clinical phenotypes of CADASIL patients. We found decreases in SvO2 and abnormal iron deposition in patients compared with healthy individuals. Also, we found associations between susceptibilities and clinical characteristics of CADASIL. These results suggest that SWIM can be used to assess clinical conditions of SVD patients.