Blood coagulation is the process by which blood changes from a liquid state to a solid state, and it is achieved through a series of coagulation reactions. The coagulation process in the human body has two processes: the exogenous coagulation pathway and the endogenous coagulation pathway, each of which requires the participation of a series of coagulation factors. Blood clotting is of great importance to the normal hemostasis of the body. If blood clotting is not completed properly, a series of symptoms of bleeding will occur, such as hemophilia A, hemophilia B, and vascular hemophilia, which are commonly seen in clinical practice, are caused by the deficiency of clotting factors. At the same time, these diseases are a genetic disorder and there is no cure for them, only plasma supplementation or other clotting factors to replace them. Therefore, once the blood does not clot easily or does not stop bleeding easily after surgery, you need to be alert to whether there is a clotting disorder and you need to check the activity of various clotting factors.