Aim To compare efficacy and safety of clopidogrel two treatment programs on preventing cardiovascular events after percutaneous coronary intervention. Methods 245 cases of patients undergoing coronary intervention were analyzed retrospectively.The patients of the observation group(120 cases) were given double of capacity clopidogrel 300 mg and 225 mg on the preoperative 48 h and 24 h respectively,then conventional oral 75 mg,qd;and the patients of the control group(125 cases) were given clopidogrel 300 mg on the preoperative 6 h single,then conventional oral 75 mg,qd.After three months,incidence rates of cardiovascular events,thrombosis and bleeding complications were compared between the two groups. Results After three months of treatment,blood coagulations of the two groups were similar(P>0.05).The incidence of reischemic event and thrombosis in observation group was significantly lower compared with the control group(P<0.01),but the incidences of bleeding of the two groups had no significant difference(P>0.05).Nobody was obliged to stop treating for drug side-effects. Conclusion giving double load of clopidogrel to patients with coronary heart disease undergoing coronary intervention before operation can reduce the incidences of reischemic event and thrombosis,and is safe.