Acute coronary syndrome (ACS) patients would still have twice heart attack, even after they had received the standard regimen, such as vascular reconstruction, oral anti-platelet therapy, and other evidence based medical therapy. Therefore, clinical have been in urgent need of a new and effective anticoagulant. OASIS-research have shown that the factor Xa play a decisive role in the process of coagulation. For ACS patients’ anticoagulant therapy, compared with normal or low molecular weight heparin, the FXa indirect inhibitor Fondaparinux sodium can not only be effective in reducing cardiovascular events, but also greatly reduce the risk of bleeding. It is especially for the patients with higher risk of bleeding and regardless the patient's age, gender, renal function and risk stratification. Based on these findings, a variety of clinical trials about small molecule oral direct inhibitor of activated factor X (FXa) anticoagulant (rivaroxaban and apixaban) gradually carried out. The conclusion has show clear pharmacokinetic and efficacy features. Rivaroxaban showed superior effectiveness in the Clinical study RECORD, making it become the first clinical application anticoagulant and not require anticoagulation monitoring. It is proved that rivaroxaban reduce the mortality from deep vein thrombosis, pulmonary embolism and all-cause by 18.9%. Take off to want: it will not increase the risk of bleeding. Rivaroxaban has been used for preventing vein thrombos in adult elective total hip or total knee replacement. Related trials in the prevention of stroke leading by atrial fibrillation and secondary prevention of acute coronary syndrome (ACS) is in progress. APPRAISE studies show that aspirin or aspirin plus clopidogrel therapy added to 5mg or 10mg apixaban may have therapeutic potential in the hope to prevent second heart attack in ACS patients. And the further tests hope the combination based on standard regimen can effectively reduce the cardiovascular events, stroke and mortality in ACS patients. Currently, apixaban clinical trials in prevention of venous thrombosis and prevention of stroke caused by atrial fibrillation are also on going. Current studies tend to show that, compared with placebo, oral factor Xa inhibitor base on standard regimen can give available benefits in ACS patients. But these findings still need further large-scale controlled studies to confirm the statistical significance.