MicroRNA (miRNA) is a kind of evolutionarily highly conserved noncoding small molecule single stranded RNA (about 18-24 nucleotides), which negatively regulates gene expression at posttranscriptional level. Vulnerable plaques refer to plaques that are easy to form thrombus or may rapidly develop into criminal lesions in the process of atherosclerosis. Research shows that miRNA is involved in almost all steps of atherosclerosis, including endothelial cell and vascular smooth muscle cell injury and dysfunction, monocyte infiltration and platelet dysfunction, and plays a beneficial or harmful role. MiRNA will also become a new field to further study the mechanism of bidirectional regulation of vulnerable plaque by traditional Chinese medicine.