In total, 97 acute ST-segment elevation myocardial infarction (STEMI) patients who received an emergency percutaneous coronary intervention (PCI) were enrolled and divided into a ticagrelor group and a clopidogrel group. Thrombolysis in myocardial infarction (TIMI) blood flow and the corrected TIMI frame count (CTFC) were used to assess the blood perfusion of culprit vessels. Thromboelastography (TEG) was used to evaluate the antiplatelet effect of drugs. The results showed that the incidence of TIMI grade III blood flow in the ticagrelor group was significantly higher than that in the clopidogrel group. The CTFC in the anterior descending, circumflex, and right coronary arteries was statistically significantly lower in the ticagrelor group as compared with that in the clopidogrel group. At 2 h and 7 d postdrug treatment, the adenosine diphosphate-induced platelet inhibition rate (ADP%) in the ticagrelor group increased significantly as compared with that in the clopidogrel group, and the platelet aggregation rate of the ADP pathway (MAADP) decreased significantly in the ticagrelor group versus that in the clopidogrel group. In conclusion, ticagrelor significantly improved TIMI blood flow and had a better antiplatelet effect than clopidogrel in STEMI patients undergoing an emergency PCI.