A mass of evidence has showed that atherosclerosis is a chronic inflammatory disease,and monocytes play a crucial role in the pathogenesis of atherosclerotic plaques.It is found that in recent studies monocytes in human peripheral blood are heterogeneous.There is a growing awareness that distinct functional monocyte subsets play different roles in several inflammatory and immunological diseases,like atherosclerosis,rheumatoid arthritis,Kawasaki disease.This review aims to make a brief summary for the phenotype and function of monocytes as well as discussion about their correlation to atherosclerosis in mice and humans.