Prothrombinogen activity is a commonly used clinical indicator of coagulation function, and low activity is an important indicator for determining the severity and prognosis of hepatocellular necrosis. Liver is an important organ of coagulation factors, when the synthesis of coagulation factors decreases the prothrombinogen activity is significantly reduced, it is an important value for the evaluation of liver damage and prognosis, when liver function is impaired, the synthesis of coagulation factors is reduced and the coagulation function is abnormal. Congenital deficiency of coagulation factors II, V, VII, and X and hypo (no) fibrinogenemia, disseminated intravascular coagulation, vitamin K deficiency, the presence of anticoagulant substances in the circulation, such as heparin and FDP, and the presence of inhibitors of coagulation factors II, V, VII, and X in the circulation can also lead to low thromboplastin activity. When patients have low prothrombin activity, they should follow the doctor’s instructions to find out the specific causes, and should not judge or diagnose on their own based on a single test result, but should consult the doctor in time, who will analyze and diagnose them according to the specific situation.