Objective: This study aims to investigate the efficacy and safety of dual antiplatelet therapy (DAPT) with ticagrelor and aspirin in elderly patients with Acute Coronary Syndrome (ACS). Methods: A total of 432 patients with ACS who underwent Percutaneous coronary intervention (PCI) were enrolled into the study. These patients were divided into three groups, according to age: non-elderly group (age: <60 years old, n=167), elderly group (age: 61-79 years old, n=209), and very elderly group (age: >= 80 years old, n=56). TIMI blood flow grade, TIMI myocardial perfusion grade (TMPG), major complications, 1-year follow-up bleeding events and the primary endpoint were observed and investigated after treatment with DAPT after PCI. Results: TIMI blood flow, TMPG, reinfarction during hospitalization, post-infarction angina pectoris, severe arrhythmia, incidence of cardiac function and cardiogenic shock (Killip III or above), incidence of total, severe and moderate bleeding events, and the primary and secondary endpoints at 1-year follow-up in the very elderly group were significantly higher, compared with the elderly group and non-elderly group. Conclusions: The probability of complications and hemorrhage was high in very elderly patients with ACS after DAPT with ticagrelor and aspirin following PCI.