Abstract: AIM To investigate the differences in clinical application of tigrelor and clopidogrel and to explore the efficacy and safety of ticagrelor and clopidogrel in acute coronary syndrome (ACS) patients undergoing elective percutaneous coronary intervention (PCI). METHODS 2 276 cardiovascular patients in Xijing Hospital were selected from which 1159 were diagnosed as ACS and undergoing PCI. The patients were divided into ticagrelor group and clopidogrel group. Baseline data, major adverse cardiovascular events (MACE, including cardiovascular death, myocardial infarction, ischemic stroke) and major bleeding events (TypeⅡ, TypeⅢ and TypeⅤ set by Bleeding Academic Research Consortium) were compared between the two groups. RESULTS Higher TNI, lower EF value, more stent numbers, maximal stenosis rate, more multiple complex lesions, fewer transradial approach, and more multiple PCI were observed in ticagrelor group (P<0.05). Between the two groups, there was no statistically significant difference in MACE events (15.18% vs. 12.59%, HR=1.226, 95% confidence interval 0.867-1.735, P=0.249) and in serious bleeding events (0.66%: 0.73%, HR=1.093, 95% confidence interval 0.212-5.634, P=1). CONCLUSION Clinicians commonly to use ticagrelor for severe ACS cases even though clinically there is no significant difference in the efficacy and safety of ticagrelor and clopidogrel for post-PCI ACS patients.