Matrix metalloproteinase-8 （MMP-8） is one of the most important members of matrix metalloproteinase family. Recent studies have shown that MMP-8 plays a vital role in the development of atherosclerosis. MMP-8 induces the formation and instability of atherosclerotic plaque via degrading collagens and other bioactive substance, and regulating the function of endothelial cells, smooth muscle cells, neutrophils and stem cells. In addition, MMP-8 is related with the occurrence and prognosis of coronary heart disease, and MMP-8 gene polymorphism is associated with the progression of atherosclerosis. In this review, we summarized the recent findings concerning the bioactivities of MMP-8 in atherosclerosis and the related mechanism of MMP-8 during atherosclerosis development, in order to find the biomarker and novel therapeutic target for atherosclerosis.