Objective To compare the bleeding risk and curative effect in the elderly (≥75 years old) and middle-aged patients (<60 years old) suffering from acute coronary syndrome (ACS) treated with different regimens of dual antiplatelet therapy (DAPT), aspirin combined with clopidogrel or with ticagrelor. Methods A total of 416 consecutive ACS patients admitted in our hospital from March 2014 to May 2015 were enrolled in this study. And all of them underwent thromboelastography (TEG). According to their age and antiplatelet regimen, they were divided into 4 groups, that is, ＜60 years old and treated with aspirin+clopidogrel (＜60C group), ≥75 years old and treated with aspirin+clopidogrel (≥75C group), ＜60 years old and treated with aspirin+ticagrelor (＜60T group), and ≥75 years old and treated with aspirin+ticagrelor (≥75T group). All the patients were followed up for 1 year. The occurrences of major adverse cardiovascular events (MACE) and bleeding events were recorded and compared in the groups. Results There were no significant differences in the occurrence of MACE, maximal amplitude (MA) value obtained with TEG, and inhibitory rate of arachidonic acid (AA)-induced platelet aggregation (AA-IPA) in each group (P>0.05). The inhibitory rate of adenosine diphosphate-induced platelet aggregation (ADP-IPA) was obviously higher in the same-aged patients treated by aspirin combined with ticagrelor than those with clopidogrel (P＜0.05), but no difference was found in the ＜60T group and ≥75T group (P=0.828), and the ADP-IPA rate was remarkably lower in the ≥75C group than the ＜60C group (P=0.011). The occurrence of bleeding risk was significantly higher in the same-aged patients treated with aspirin+ticagrelor than with clopidogrel (P＜0.05), but most of them was type Ⅰ non-fetal bleeding events. There was no difference in bleeding risk between the ＜60T group and the ≥75T group (P=0.392). Cox regression analysis revealed that blood glucose level (B=0.111, RR=1.117,95%CI:1.014-1.231, P=0.025), estimated glomerular filtration rate (eGFR, B=-0.023, RR=0.977,5%CI:0.961-0.993, P=0.005), and heart rate (B=0.040, RR=1.041,5%CI:1.013-1.070, P=0.004) were risk factors for MACE. Logistic regression analysis showed that different strategies of DAPT (B=3.527, OR=34.025,5%CI:9.560-121.101, P<0.001) and sex (B=1.126, OR=3.085,5%CI:1.083-8.788, P=0.035) were risk factors for bleeding events. Conclusion The clinical efficacy of aspirin+ticagrelor is not superior to that of aspirin+clopidogrel, and the former regimen is associated with higher risk of type Ⅰ bleeding. No difference is observed in the bleeding risk in the patients treated with aspirin+ticagrelor at different age period.