Pulmonary arterial hypertension (PAH) is classified as group 1 of pulmonary hypertension. PAH is a progressive and fatal disease of the pulmonary artery. The major pathogenesis of PAH is sustained vasoconstriction and vascular remodeling of the pulmonary artery. These pathogeneses cause progressive elevations in pulmonary vascular resistance and pulmonary arterial pressure (PAP) in PAH patients. Elevated PAP leads to right heart failure and finally death. A central aspect of pulmonary vascular remodeling is medial hypertrophy, which is caused by the enhanced proliferation and reduced apoptosis of pulmonary arterial smooth muscle cells (PASMCs). Excitable abnormality in the pulmonary artery of PAH patients are mostly mediated by an elevated cytosolic [Ca²⁺]. Enhanced Ca²⁺ signaling have been reported in PASMCs from PAH patients. PASMCs express several Ca²⁺-permeable channels including voltage-dependent Ca²⁺ channels, receptor-operated Ca²⁺ channels, and store-operated Ca²⁺ channels. The expression levels of these Ca²⁺ channels are increased in the lung tissues and PASMCs of PAH patients. Targeting these Ca²⁺ channels in PASMCs may help develop novel therapeutic approach for PAH.