Protease-activated receptors (PARs) are members of the G protein-coupled receptor family, including four subtypes, PAR1 to PAR4, each with seven transmembrane domains. They are widely distributed in various cells and tissues, such as vascular endothelial cells, smooth muscle cells, and platelets. PARs are activated by proteolytic cleavage and participate in regulating vascular tone, inflammatory responses, and the coagulation process. They activate multiple signaling pathways, including IP3, DAG, and cAMP. Mutations or abnormal expression of PARs are associated with thrombosis, inflammatory diseases, and cancer development.