There are two pathways of coagulation in the human body, endogenous and exogenous. The endogenous coagulation pathway is initiated by coagulation factor D.E., which leads to hemostasis through a further cascade of reactions, culminating in the activation of fibrin and the formation of a thrombus. Coagulation factor D.E. is known as a contact or surface factor, and is activated from the zymogen form of coagulation factor D.E. when collagen is exposed by damage to the vessel wall or when blood comes into contact with a foreign surface, becoming D.E.D. D.E. can further activate coagulation factors Ⅺ, Ⅸ, VIII, X, V, and II, and ultimately activate fibrinogen to form a fibrin thrombus. When coagulation factor Ⅻ is deficient, it can cause endogenous coagulation can not be initiated, thus affecting the body’s coagulation function, bleeding with easy spontaneous bleeding and other manifestations. If repeated nosebleeds, bleeding gums and other manifestations, it is recommended to go to the hospital to improve the coagulation function test, to clarify the cause of the disease, in order to receive treatment under the guidance of the physician.