Abstract： Objective To observe the clinical efficacy and application value of preoperative application of hydrochloride tirofiban in patients with acute coronary syndrome(ACS) by percutaneous coronary intervention (PCI).Methods 60 ACS patients underwent PIC surgery were randomly divided into observation group and control group.All patients underwent preoperative and postoperative regular routine anti-angina and acute myocardial infarction treatment,the observation group was given the hydrochloride tirofiban in 1h before surgery of emergency PCI,the control group received conventional therapy.The bleeding and thrombocytopenia occurrence during hospitalization of the two groups were observed,before surgery and 1 month after surgery the cardiac function of the two groups were compared,1 month after surgery the occurrence of adverse cardiovascular events were recorded.Results The bleeding incidence of observation group was 6.7％,the control group was 23.3％,the difference between two groups was significant ( x2 =15.594,P ＜ 0.01 ) ; The thrombocytopenia occurrence of observation group was 3.3％,the control group was 10.0％,the difference between two groups was significant( x2 =13.366,P ＜ 0.01 ).1 month after surgery the LVEF,CO and E/A of the two groups increased significantly,compared with the prior-treatment,the difference was significant (P ＜ 0.05 ),and the difference was significant between the two groups( P ＜ 0.05 ) ;The occurrence of adverse cardiovascular events of observation group was 33.3％,the control group was 66.7％,the difference between two groups was significant(x2 =8.924,P ＜ 0.01 ).Conclusion The hydrochloride tirofiban is a safe and effective anti-platelet drugs.Preoperative application of hydrochloride tirofiban in patients with ACS by PCI can reduce the occurrence of cardiovascular events.