Coagulation factors are generally defined as procoagulant substances contained in blood plasma, also known as clotting factors, of which at least 16 exist. According to the order of their discovery, Roman numerals were used to give official names, such as factor II, factor VII, etc.. Later, it was found that factor IV is calcium ion and factor VI is activated factor V. Therefore, the naming of factor IV and factor VI was canceled. 1. The physiological role of coagulation factors is to be activated when blood vessels bleed, and platelets adhere together to fill the vascular fistula, a process known as coagulation. 2. Most coagulation factors are synthesized in the liver, and a few are synthesized in endothelial cells and other locations. Among them, the synthesis of factors II, VII, IX, and X requires the participation of vitamin K, also known as vitamin K-dependent coagulation factors. 3. The reference range of most of the coagulation factor activities in the body is between 50% and 150%. Fibrinogen, i.e., factor I, is converted into soluble fibrin monomers under the action of thrombin, and then converted into cross-linked fibrin network in the presence of factor XIII and calcium ions, which ultimately plays a role in hemostasis.