Pulmonary arterial hypertension (PAH) is a fatal and complex disease characterized by multifactorial involvement in pulmonary vascular remodeling, leading to heart failure. It is difficult to treat and has a poor long-term prognosis. Recent studies highlight the significant role of epigenetic modulation in the pathophysiological progression of PAH, offering new therapeutic approaches to improve clinical outcomes. This article summarizes the role of epigenetic modulation in the development and progression of PAH, focusing on deoxyribonucleic acid methylation, ribonucleic acid methylation, histone modifications, and non-coding ribonucleic acid, in order to understand the role of epigenetic modulation in PAH and identifying new evaluation indexes and therapeutic targets, thereby improving the prognosis of PAH.