Abstract: Objective To study the early anti-platelet effect of aspirin after coronary artery bypass grafting（CABG）Methods Thirty patients were selected to undergo CABG and 30 patients were selected to undergo off-pump coronary artery bypass grafting（OPCABG）.Their platelet count and adenosine diphosphate-induced platelet aggregation（PAG）rate were recorded before and 1,5,10 days after operationResults The number of platelets decreased transiently and then increased significantly in both groups after treatment with aspirin,and was significantly greater than that before operation（P＜0.01）,especially in CABG group.The PAG rate increased in both groups after operation than before operation（P＜0.05）.The number of platelets returned to normal 10 days after OPCABG,and was still higher in those after CABG than before CABG（P＜0.05）Conclusion Aspirin cannot significantly inhibit the early aggregation function of platelets after CABG due to aspirin resistanceTherapy;Aspirin/Aspirin Resistance.