Objective:To compare the efficacy and safety between Fondaparinux and low molecular weight heparin(LMWH) in treat-ing acute myocardial infarction(AMI) without revascularization at early stage. Methods:Three hundred and two patients with AMI without revascularization at early stage were randomly divided into Fondaparinux group(152 cases) and LMWH group(150 cases). The cardiovascular event and bleeding incidences within 7 d and 30 d after the treatment in both group were observed. Results:The incidences of cardiovascular events (angina,recurrent myocardial infarction,death,vicious arrhythmia,heart failure) within 7 d in Fondaparinux group were obviously lower than those in LMWH group(8.6% vs. 18.7%,2.6% vs. 8.7%,2.6% vs. 8.0%,3.6% vs. 10.0% and 11.8% vs. 21.3%). The incidences of major adverse cardiac events(recurrent myocardial infarction,death,refractory myocardial ischemia) within 30 d in Fondaparinux group were obviously lower than those in LMWH group(3.9% vs. 10.0%,3.9% vs. 10.7%,3.3% vs. 13.3% and 8.6% vs. 21.3%). There was no significant difference in incidences of bleeding events between the two groups. Conclusions:Fondaparinux can significantly reduce cardiovascular events without increasing bleeding events in patients with AMI but not undergoing revascularization at early stage.