Abstract: Objective To analyze the incidence and influencing factors of high on-treatment platelet reactivity(HPR)using thrombelastography(TEG) in patients undergoing percutaneous coronary intervention(PCI) and dual anti-platelet therapy,and explore the relationship between the incidence of HPR and prognosis. Methods The data was collected from335 patients undergoing PCI and TEG examination in our hospital from January,2013 to December,2014. All patients were receiving dual anti-platelet therapy with Aspirin and clopidogrel. The medical records and prescription were reviewed. The platelet inhibition rate was examined with TEG and the rate of HPR was calculated,and the risk factors were analyzed. The follow-up for the clinical events was carried out to analyze the relationship between the occurrence of HPR and prognosis. SPSS 19. 0 statistical software was used for data analysis. Results The prevalence of HPR after treatment with aspirin was 35. 2%(118/335),with clopidogrel was 34. 6%(116/335). The occurrence of HPR was affected by some clinical conditions. 308 patients were followed up,and 289 of them did not change the anti-platelet drugs. HPR was correlated at some extent with the ischemic events in patients receiving aspirin treatment(P=0. 003),nut not for clopidogrel treatment. Conclusion The incidence of HPR by TEG is prevalent in clinical practice,and some clinical conditions may affect HPR. HPR in patients receiving aspirin treatment is related with ischemic events.