Monocytes are important mediators of the innate immunity and play crucial roles in various inflammatory diseases, including vascular inflammation and atherosclerosis (As). Hyperlipidemia can accelerate cardiovascular disease progression, especially As. Under hyperlipidemia, circulating monocytes can take up lipids, become foamy monocytes and change phenotypes, which may contribute to development of As. For a long time, the response of monocytes and their different subtypes to hyperlipidemia and the effect on As have been the focus of research. This paper discusses the characteristics of monocyte subtypes in human and mice, the effects of hyperlipidemia on monocytes, and the effects of monocytes on As, and focuses on the research progress of monocytes affecting As process through lipid phagocytosis, foam cell formation, patrolling and migration into plaques.