Aim To explore the effect of trimetazidine on cardiomyocyte apoptosis after coronary microembolization （CME） in swine. Methods Fifteen swine were randomly and equally assigned into sham-operated （control） group,CME group and trimetazidine group.CME was induced by injection of microspheres selectively into left anterior descending artery for control group,the same dose of normal saline was substituted for microspheres and those in trimetazidine group were pretreated with trimetazidine 30 min before microspheres injection.Cardiac function was assessed by echocardiography,cardiomyocyte apoptosis was detected by TUNEL staining,and the expression levels of caspase-8 and caspase-3 were measured by Western blot 9 h after operation. Results Compared with sham-operated group,cardiac function was significantly decreased in CME group （P<0.05） However,cardiac function was significantly improved in trimetazidine group compared with CME group （P<0.05）.Compared with control group,myocardial apoptosis rate and the levels of activated caspase-8 and -3 increased significantly in CME group （P<0.05）.Again,these effects were ameliorated by trimetazidine （P<0.05）. Conclusion Trimetazidine pretreatment suppressed post-CME myocardial apoptosis and improved cardiac function probably by inhibiting myocardial death receptor-mediated apoptotic pathway.