Objective To investigate the therapeutic effect and side effect of prourokinase (Pro-uk) on the patients with acute myocardial infarction. Method From May 2004 to May 2005, a total of 68 cases of acute myocardial infarction treated by thrombolytic agents within 6 hours after onset were divided randomly into Pro-uk group ( n = 43) and urokinase (UK) group ( re = 25). In the Pro- uk group, there were 22 eases treated with 50 mg Pro-uk and 21 cases prescribed in 60 mg Pro-uk. The patency of involved coronary artery was evaluated by using selective coronary angiography at 90 minutes after thrombolytic therapy. The incidence of early heart events, bleeding and adverse reaction, were alse observed. Results (1) The total rates of resumed patency of obstructed coronary artery (TIMI grade 2 and 3 flow) were 76.7% in Pro-uk treated patients and 52.2% in UK treated patient ( P = 0. 041). (2) The occurrence of hyporrhea was lowered more significantly in Pro-uk treated patients than in UK treated patients (P = 0.029), but there were no intracranial hemorrhage found in both group. (3) Early cardiac events and adverse reactions were similar between two groups. Conclusions Pro-UK is safe and effective for the patients with acute myocardial infarction.