Abstract: As one of the most common cardiovascular diseases, hypertension is the top priority of chronic diseases prevention and control in China. Ambient fine particulate matter (PM_2.5) is a risk factor for multiple cardiovascular diseases. In reported mechanisms by which PM_2.5 affects blood pressure, oxidative stress and inflammation play key roles. The components of PM_2.5 include black carbon, organic matters, inorganic ions, and metals, and they can stimulate different inflammatory pathways and affect blood pressure regulation in varied ways. This review summarized the potential molecular mechanisms of PM_2.5 affecting blood pressure, and focused on the roles of different components of PM_2.5 in regulating blood pressure, aiming to provide a theoretical basis and research ideas for the prevention and treatment of hypertension induced by air pollution.