Urokinase is a proteolytic enzyme extracted from human urine or renal cell tissue culture medium, which can directly activate fibrinolytic enzyme to become fibrinolytic enzyme, so as to hydrolyze fibrinolytic proteins and dissolve thrombus. The activity of fibrinolytic enzyme increased rapidly after intravenous administration of this drug, reaching a peak in 15 minutes, rising after 6 hours, and slowly returning to normal after 24 hours. Urokinase is used in the same way as streptokinase, but it is weaker than streptokinase. At present, it is mainly used in the treatment of acute myocardial infarction with intravenous thrombolysis or intra-coronary thrombolysis, and also for other thromboembolic diseases, ocular inflammation, traumatic tissue edema, hematoma, etc. In addition, there is anti - lung cancer metastasis, pregnancy poisoning, systemic lupus erythematosus also has a certain effect.