Aim To approach the change of platelet activation before and after stenting for coronary artery disease and the relationship among stable angina pectoris(SAP),unstable angina pectoris(UAP),acute myocardial infarction(AMI),number of stent implantation and platelet activation. Methods Detection of positive expression of platelet membrane glycoprotein CD62p,CD63 and thrombin-sensitive protein(TSP) was performed by flow cytometry and monoclonal antibody in 175 patients.They were divided into four groups: SAP group(48 patients with stable angina);UAP group(45 patients with unstable angina);AMI group(37 patients with acute myocardial infarction) and control group(45 patients with angiography). Results There were increased the levels of CD62p,CD63 and thrombin-sensitive protein expression after stent implantation in coronary artery disease(p<0.01),and the expression levels of UAP group and AMI group were higher than that of control group(p<0.01).The positive expression of CD62p,CD63 and thrombin-sensitive protein were related to number of stenting. The more stenting,the higher positive expression. Conclusion Unstable angina and acute myocardial infarction presented high level of platelet activation,atherosclerosis plaque rupture and prone to thrombosis.Stenting induced endothelial damage augmented platelet activation and increased the risk of thrombosis.