S100B protein is one of the large superfamily members of S100 protein， which is mainly expressed by astrocytes in the brain. During the development of the central nervous system， S100B plays a variety of roles as a neurotrophic factor and a neurosurvival protein. Clinically， S100B is usually upregulated in the pathologic process of cerebrovascular disease. As a biomarker of cerebrovascular diseases， S100B has been widely studied. This article reviews the pathogenesis， diagnosis， differential diagnosis and prognosis of S100B and cerebrovascular diseases.