Objective： To investigate the relation of clopidogrel resistance to polymorphism of adenosine diphosphate receptor (P2Y12). Methods： Three hundred and seventy patients with coronary atherosclerotic heart disease, who were admitted in hospital from May 2011 to November 2012 and underwent percutaneous coronary intervention, were enrolled in the study. All patients recieved antiplatelet therapy (oral aspirin 100 mg per night and clopidogrel 75 mg per day for >7 d). The gene polymorphisms of C34T and G52T P2Y12 receptor were detected by using DNA sequencing technique. The relationship of gene polymorphism with the incidence of clopidogrel resistance and clinical outcomes were analyzed. Results： Among 370 patients, clopidogrel resistance developed in 100 cases, including 36 males (36%) and 64 females (64%). In the C34T locus, 212 cases were of CC genotype and 158 were of CT+TT genotype; the incidence of clopidogrel resistance in CC genotype was significantly lower than that in CT+TT genotype (P<0.05). In the G52T locus, 218 cases were of GG genotype and 152 cases were of GT+TT genotype; the incidence of clopidogrel resistance in GT+TT genotype were significantly higher than that in GG genotype (P<0.05). After 1year followup, patients with CC genotype had lower incidence of angina recurrence than patients with CT+TT genetype did (13.2% vs 19.6%, χ2=4.956, P<0.05), and patients with GG genotype had lower incidence of emergency revascularization, angina, and cardiovascular composite endpoint events than patients with GT+TT genotype did (χ2=4.135,6.823,5.916, Ps<0.05). Conclusion： T34, 52 mutations on P2Y12 receptor gene may be a risk factor for clopidogrel resistance and adverse cardiovascular events.