In the past decade,microRNA(miRNA),especially its function of regulating gene expression,has received a lot of attention.More and more studies have shown that miRNA is closely related to the occurrence and development of atherosclerosis(AS).This correlation is mainly reflected in the dysfunction of endothelial cells,monocytes/macrophages and smooth muscle cells,thereby triggering and promoting the growth of AS plaques.The level of miRNA in patients'peripheral blood cells can be used as a marker to judge the severity of the disease.In addition,the development of new therapeutic methods from the perspective of miRNA is conducive to better treatment of AS.This paper summarizes the mechanism of action of miRNA in the occurrence and development of AS,and focuses on the latest progress of miRNA as a novel biomarker in the diagnosis of AS and a potential therapeutic target for AS,which provides a new theoretical basis for the clinical diagnosis and treatment of AS.