Coronary artery spasm(CAS)is a hyper-contraction of segmental coronary artery in response to multiple stimuli. At present, it's still in lack of specific diagnostic indicators of sudden cardiac death caused by CAS. This review summarizes current researches on the mechanisms of CAS and describes the roles of vascular endothelial dysfunction and vascular smooth muscle hypersensitivity in the course of CAS. Furthermore, the molecular mechanisms of the endogenous NO and endothelin-1 cause vascular endothelial dysfunction, and the phosphorylation of MLC2, Rho kinase and endoplasmic reticulum stress related to vascular smooth muscle hypersensitivity are discussed. Meanwhile, the possibility of forensic application for the related molecules on the diagnosis of sudden cardiac death caused by CAS are also explored.