Blood cells that are not directly involved in blood coagulation are mainly white blood cells and red blood cells. Blood coagulation refers to the process in which blood is transformed from a flowing, liquid state into a non-flowing, gel-like state, and is an important part of hemostasis. The basic process of blood coagulation is the limited hydrolysis of a series of proteins, which is roughly divided into three stages: the formation of plasminogen activator, thrombin formation, fibrin formation and so on. The essence is that the soluble fibrinogen in plasma, through coagulation factors, Ca++, platelets, vitamin K and other elements involved, into insoluble fibrin process. While the main function of leukocytes is defense, different kinds of leukocytes participate in the body’s defense reaction in different ways, and do not participate in blood coagulation. Whereas red blood cells contain hemoglobin and their main function is to carry oxygen and deliver it to the tissues and organs of the body. Therefore, the main role of both types of cells is not related to blood coagulation and have no important role in blood coagulation.