ObjectiveTo detect the antiplatelet effect of aspirin and clopidogrel in patients with acute cerebral infarction using a thromboelastograph(TEG) instrument in order to guide the individualized adjustment of anti-platelet aggregation drugs. Methods82 patients with acute cerebral infarction were selected, and all patients were treated with aspirin and clopidogrel for 7 days, a TEG instrument was used to detect arachidonic acid (AA) -induced inhibition rate of platelet aggregation and adenosine diphosphate (ADP) receptor-induced inhibition rate of platelet aggregation. The AA pathway and ADP receptor-induced inhibition rate of platelet aggregation, as well as the response differences of the patients between aspirin and clopidogrel therapy were compared. At the same time, 40 patients with acute cerebral infarction patients were selected as the control group, received 100 mg caspirin for 7 days. The parameters of TEG (R time、K time、α angle and MA) between the two groups were compared. Results① Patients with acute cerebral infarction received aspirin and clopidogrel for antiplatelet therapy, the inhibition rate of aspirin for the AA pathway was significantly higher than that of clopidogrel for the ADP receptor pathway (P<0.01). ②Of those who had good response to aspirin, 4 had no response to clopidogel and 15 had low response to clopidogel; Of those who had a good response to clopidogel, only 1 had low response to aspirin. Of those who had low response to clopidogel, 3 had no response to aspirin,5 had low response to aspirin ,6 had a good response to aspirin ,and 15 had good result. The two efficacies had some relevance (P<0.01).A total of 62 patients had a good + effective response to aspirin, and 20 had low response +ineffective to aspirin, while 42 and 38 patients had good + effective and low response + ineffective to clopidogel .There was significant difference in efficacy between the drugs (P<0.01). There were no significant difference in R time、K time、α angle and MA between control group and dual antiplatelet group (P>0.05). ConclusionTEG instrument is valuable in assessing the efficacy of antiplatelet therapy in patients with acute cerebral infarction , The inhibitory effect of platelet aggregation of aspirin is stronger than that of clopidogrel. The patients show differential response to aspirin and clopidogrel therapy. Some patients who have low response to clopidogrel may response well or may be effective to aspirin. There was no significant difference on blood coagulation between dual antiplatelet therapy and aspirin alone.