Type 2 diabetes mellitus (T2DM) as well as vascular cognitive impairment and dementia (VCID), are both chronic diseases, severely affecting patients, families, and society. A growing number of studies have found that T2DM may double the incidence of cognitive impairment. To help patients with T2DM prevent cognitive dysfunction more scientifically, as well as providing researchers with clearer research ideas, we summarized the risk factors, mechanisms and prevention methods of VCID which is induced by T2DM. This is a great significance for patients with T2DM to prevent the occurrence of VCID, meanwhile, it provides a reference for future researches on the relationship between T2DM and VCID.