This study aims to compare and evaluate safety and antithrombotic effect of tirofiban and urokinase in emergency percutaneous coronary intervention (PCI). Twenty patients with relatively large thrombus burden in emergency PCI were selected; 12 patients received tirofiban and others received urokinase during operation. Operation success rate, thrombus score and incidence of hemorrhagic complications and major adverse cardiac events [MACEs, including death, acute myocardial infarction (AMI) and emergency revascularization] during perioperation and three months after discharge were recorded. Coronary thrombi in tirofiban group disappeared earlier than that of urokinase group; the incidence of bleeding was comparable between two groups; no MACEs were observed at hospital and during threemonth follow-up. In tirofiban group, thrombus score significantly decreased and operation success rate was 100%, without death, recurrent MI and target vessel revascularization. Tirofiban is safe and effective in emergency PCI, which shows antithrombotic effect and significantly decreases thrombus score.