Abstract: A change in vascular smooth muscle cell (VSMC) phenotype, known as converting from a contractile state into a synthetic phenotype, is a crucial event in vascular remodeling, which determines the occurrence, development and prognosis of cardiovascular diseases such as pulmonary hypertension and atherosclerosis. Research shows that the expression level of key signaling molecules, which controls the phenotype change of VSMC, is regulated by microRNA (miRNA), a type of non-encoding RNA. In this article, we provide a review of miRNA in the regulation of VSMC phenotype changes with a focus on the key molecules in MAPK, TGFβ/Smad and PI3K/Akt signaling pathways.