Abstract: Objective To compare the efficiency of verifynow antiplatelet treatment monitor system and flow cytometer in detecting the antiplatelet function of clopidogrel. Methods Venous blood samples were randomly taken from 72 outpatients and inpatients.Platelet aggregation function was assayed with the verifynow antiplatelet treatment monitor system and flow cytometer. Results The P2Y12reaction unit（PRU） detected with the verifynow antiplatelet treatment monitor system was ＜240 in 19 individuals（26.4%）.The active value of platelet membrane glucoprotein molecule PAC-1（receptor of Fg,Ca2+ and GP Ⅱb / Ⅲa complex） was 20-60 in most individuals,＜20 in 2 individuals,and ＞60 in 12 individuals.The active value of platelet membrane glucoprotein molecule CD62p（P selectin） was ＜10 in most individuals and ＞20 in 3 individuals.The active value of PAC-1 was positively correlated with that of CD62p（r=0.812,P＜0.01）.The active value of PAC-1 and CD62p was positively correlated with the PRU（r=0.565,r=0.314,P＜0.01）.The PRU was negatively correlated with inhibition percentage of platelet aggregation detected with the verifynow antiplatelet treatment monitor system（r=-0.080 2,P＜0.01）. Conclusion The efficiency of verifynow antiplatelet treatment monitor system and flow cytometer is similar in detecting the antiplatelet function of clopidogrel.However,it is more tedious to use flow cytometer than to use verifynow antiplatelet treatment monitor system in detecting the antiplatelet function of clopidogrel.