Objective: To compare clinical outcomes and safety of eptifibatide or tirofiban in patients with acute coronary syndrome(ACS) undergoing percutaneous coronary intervention(PCI). Methods:Thirty-six patients with ACS(unstable angina/non-ST-segment elevation myocardial infarction, UA/NSTEMI) who underwent PCI were randomly divided into two groups to receive eptifibatide or tirofiban treatment. Eptifibatide or tirofiban was predominantly initiated in the catheter laboratory before the intervention. In-hospital and 30-day MACE outcomes; bleeding as well as platelet counting were investigated in those two groups. Results:No in-hospital and 30-day MACE event occurred in the two groups. The number of ischemia leads after treatment reduced compared to that before PCI in the two groups. There was improvement in the number of ischemia leads for 24 h after administration in the tirofiban group than those in eptifibatide group(4.21±2.46 vs. 3.89±3.31, P =0.03). The two groups showed no incidence of massive bleeding. Minor bleeding rates were 16.7% and 22.2% in the two groups respectively. Conclusion:Eptifibatide as an adjunct to PCI may further decrease the incidence of ischemia event in patients with ACS and improve the safety, but its long-term efficacy and side effects need further observation.