Pulmonary artery hypertension (PAH) is a chronic progressive disease characterized by persistent elevation of pulmonary arterial vascular pressure. The disease severely limits the function of the right ventricle, causing organ failure and finally leading to death. Despite significant advances in pharmacological treatments, PAH remains an incurable disease with high morbidity and mortality. The histopathological change of PAH is featured by remodeling of the pulmonary vascular. Abnormal proliferation of pulmonary artery smooth muscle cells in peripheral vascular is 1 major pathological finding of pulmonary vascular remodeling. Current therapeutics available for PAH primarily aim at inhibiting the pulmonary vasoconstriction and resisting pulmonary vascular remodeling. To date, only some inhibitors targeting proliferative signaling pathways have been used to suppress the proliferation of pulmonary artery smooth muscle cells and reverse pulmonary vascular remodeling. However, because of serious side effects, their clinical use is limited, and more validation is needed before the inhibitors can be transferred into clinical use. This review will focus on signal mechanisms of vascular remodeling in the development of PAH and give an overview of recent advances in research on inhibitors targeting proliferative pathways.