Almost all life on earth has an internal mechanism-circadian rhythm, and the circadian clock that controls the circadian rhythm has been revealed as an important regulator of physiology and disease. Circadian rhythm is closely related to atherosclerosis(As). Various studies have shown that impaired circadian clocks and disturbed sleep can affect hematopoiesis process and glucose and lipid metabolism of As,and change the cellular behavior in local plaque lesions. At the molecular level, circadian rhythm can regulate atherosclerotic inflammation and vascular remodeling through the Toll like receptor (TLR) pathway, improve endothelial function and insulin signaling through the protein kinase B (Akt) pathway, and affect the recruitment of monocytes and activation of lymphocytes through the CCL2-CCR2 signal axis.This review discussed the role and molecular mechanisms of circadian rhythm in As, in order to better understand the connection between As and the circadian clock system.