Patients having myocardial infarction with ST-segment elevation often cannot undergo timely primary percutaneous coronary intervention (PCI) and therefore receive fibrinolysis. The role and optimal timing of routine PCI after fibrinolysis have not been established. 368 high-risk patients who had myocardial infarction with ST-segment elevation and fibrinolytic therapy were divided into early PCI group (n = 162), PCI within 6 h after fibrinolysis and standard treatment group (n = 206), and single drug therapy or PCI after one day of fibrinolysis. All patients received aspirin, tenecteplase, urokinase, pro-urokinase, streptokinase, rt-pa, Tnk and heparin, while enoxaparin or clopidogrel was recommended. The MACE was the composite of death, reinfarction, recurrent ischemia, new or worsening congestive heart failure, or cardiogenic shock during the in-hospital periods. Cardiac catheterization and PCI was performed for 34% of the patients in the standard-treatment group and 100% of the patients in the early-PCI group. A follow-up evaluation at in-hospital days was completed for all patients. The major adverse cardiac event occurred in 3.1% of the patients in the early-PCI group and in 17.0% of the patients in the standard-treatment group. There were no significant differences between the groups in the incidence of major bleeding. Among high-risk patients who had myocardial infarction with ST-segment elevation and who were treated with fibrinolysis, early PCI within 6 h after fibrinolysis decreased mortality in hospitals than standard treatment.