Objective:To compare the effect of ticagrelor and clopidogrel on maximum aggregation rate (MAR) and high-sensitivity C-reactive protein(hs-CRP) of clinical outcomes,security,platelets in patients with acute ST-elevation myocardial infarction(STEMI). Methods:A total of 109 consecutive patients with STEMI was randomized into two groups. One group received 180 mg loading dose ticagrelor followed by 90 mg twice daily thereafter,while the other received 600 mg clopidogrel followed by 75 mg daily thereafter. The patients of two groups were all successfully underwent acute percutaneous coronary intervention (PCI). The incidence of major adverse cardiovascular events (MACE) and hemorrhagic events of the two groups were compared after 30 days. MAR and hs-CRP levels were detected before and after 7 days and 30 days with therapy. Results:The differences of MACE and hemorrhage rate during 30 days between two groups were not statistically significant(7.3% vs 1.9%,P = 0.363;7.3% vs 14.8%,P = 0.208). Baseline characteristics,platelet aggregation and hs-CRP were similar between the two groups. ADP-induced platelet aggregation detection showed that the ticagrelor group has a lower MAR than the clopidogrel group both at 7 days and 30 days after administration[7 days(22.80 ± 6.37)% vs (30.96 ± 8.90)%,P < 0.001;30 days(22.26 ± 5.85)% vs (30.87 ± 8.54)%,P < 0.001]. After 7 and 30 days administration,the inhibitory rate of blood platelet aggregation was lower than 30% in 6 cases(10.9%)and 5 cases(9.1%)of the clopidogrel group,while in the ticagrelor group,no case of platelet aggregation inhibition rate was lower than 30%. The hs-CRP concentration at baseline,7 days and 30 days were similar between two groups(P > 0.05). Conclusion:Administration of ticagrelor results in more intense inhibition of platelet aggregation than administration of clopidogrel. The safeties of ticagrelor and clopidogrel are similar. No significant clinical benefit was acquired with ticagrelor in short-term evaluation.