Objective To observe the incidence of aspirin resistance (AR) in the patients with acute myocardial infarction after percutaneous coronary intervention (PCI) by thromboelastography (TEG), and analyze its influencing factors to provide the basis for individualized treatment. Methods A total of 170 patients with acute myocardial infarction undergoing PCI in our hospital in 2014 were enrolled in this study. Their clinical data and TEG results were collected and analyzed. The patients were divided into aspirin sensitive group (n＝105) and AR group (n＝65) based on the inhibitory rate of arachidonic acid (AA). Univariate and multivariate logistic regression analyses were carried out on the obtained clinical data of the two groups. Results The incidence of AR was 38.2% (65/170), and the inhibitory rate of AA was (32. 14±12. 77)% in AR group, and (74. 48±16. 19)% in aspirin sensitive group. Histories of long- term smoking and hyperlipidemia were statistically different between the two groups (P＜0.05), but sex, age, long- term drinking, diabetes, hypertension, arrhythmia, indices of blood routine and biochemical examination, and TEG parameters had no statistical discrepancies (P＞0.05). Multivariate regression analysis showed that long- term smoking was an influencing factor of AR. Conclusion Long- term smoking may be a risk factor for AR in the patients with acute myocardial infarction after PCI.