Atherosclerosis is a chronic inflammatory disease of artery. Abnormal activation of monocytes/macrophages is closely related to the development of atherosclerosis. Recent studies have found that monocytes/macrophages can undergo metabolic reprogramming by trained immunity, promote inflammatory responses, which accelerate the progression of atherosclerosis and increase cardiovascular incidents. In this review, we discuss the function and mechanisms of metabolic reprogramming of monocytes/macrophages in the trained immunity, which may provide new therapeutic targets and methods for the prevention and treatment of atherosclerosis.