Inflammation plays an important role in atherosclerosis. Myeloperoxidase,a biomarker of activation of neutrophils,is an enzyme that is released from activated neutrophils,monocytes and macrophages. Myeloperoxidase and its oxidase products promote the formation of atherosclerotic,and stimulus to thrombogenecity and unstable plaque. Therefore，myeloperoxidase is closely related with the incidence of acute coronary syndrome. Myeloperoxidase is an early biomarker of acute coronary syndrome,and that can predict the incidence of the major adverse cardiac events.