Abstract: Pulmonary hypertension is a rapidly progressing disease of the lung vasculature with poor prognosis, ultimately leading to right heart failure and death. The remodeling of small pulmonary arteries represents an important pathological characteristic of pulmonary hypertension. Pulmonary arterial smooth muscle cells (PASMCs) located in the middle layer of pulmonary artery exhibit hyperproliferation and resistance to apoptosis, which is the main initiator of pulmonary vascular remodeling and similar to that seen in tumor cells. In this review we focus on the signaling pathways that play a key role in PASMCs proliferation and the latest research progress on inhibitors targeting cell proliferation pathways to provide a new perspective for the treatment of PH．