Objective:To establish a method of detecting cyclooxygenase (COX)-1,COX-2 and P-selectin in platelet-rich plasma (PRP) by flow cytometry(FCM),and to detect the expressions of COX-1,COX-2 and P-selectin in PRP from coronary artery disease (CAD) patients without using anti-platelet agents. Methods:Twenty CAD patients were recruited,who were going to receive coronary artery bypass graft(CABG) and had withdrawn aspirin and clopidogrel for at least 7 days. After overnight fasting,the patients’ venous blood was drawn and processed,then the PRP was incubated with fluorescence labeled antibody,and COX-1,COX-2 and P-selectin were detected by FCM. Results:The positive percent of COX-1,COX-2 in PRP of the enrolled 20 patients were (39.67 ± 9.20)% and (4.11 ± 2.74)%,respectively,and the positive percent of P-selectin in platelet was (13.56 ± 8.07)% after incubated with saline and(24.08 ± 13.49)% after incubated with arachidonic acid,the real positive percent of P-selectin in platelet was(10.27 ± 7.40)%. Conclusion:FCM can effectively detect the platelet expressions of COX-1,COX-2 and P-selectin. There would be ethnic differences between Chinese Han and Caucasian regarding the platelet expressions of COX-1,COX-2 and P-selectin in CAD patients.