To investigate the clinical efficacy and safety of Ticagrelor in the application of (ACS) PCI in patients with acute coronary syndrome. 114 cases of acute coronary syndrome (ACS) patients with PCI treatment from April 2014 - March 2015 in our hospital have been selected, and then 57 cases (Clopidogrel loading dose 300mg before PCI, maintenance dose 75mg qd) were randomly divided into control group, and 57 patients (Ticagrelor loading dose 180mg before PCI, maintenance dose of 90mg bid). Two groups were observed by the incidence of thromboembolic events and coronary blood flow in PCI surgery, and patients were observed after the PCI surgery in 1 month, 3, 6, and 12 months following up. Also, the observation of the recurrent angina, myocardial infarction, sudden cardiac death, stroke and other cardiovascular and cerebrovascular adverse events and adverse drug reactions to the patients after the surgery with one year was conducted. In both groups, the occurrence of acute thrombosis was similar, there was no statistically significant difference (P> 0.05); the intraoperative coronary blood flow grade of treatment group was significantly better than that of the control group, and the difference was statistically significant (P <0.05). 16 cases of ACS occurred in the control group, and 7 cases occurred in the treatment group (P <0.05); the occurrence rate of breathing difficulty in control group was significantly lower than that of in the treatment group (p <0.05); the occurrence rates of bleeding in the control and treatment groups were 8.8%, 10.5% respectively, and no statistically significant difference (p> 0.05); no sudden cardiac death and stroke in two groups (p> 0.05). To the PCI patients with acute coronary syndrome, the application of Ticagrelor could improve the coronary blood flow in patients with surgery, and then reduced the recurrence rate of postoperative ACS event, and the incidence of bleeding events would not increase.