The experiment of recirculating blood perfusion device showed that trimetazidine (TMZ ) 30 mol/L could significantly inhibit the arrhythmias induced by ischemia and reperfusion, decrease the content of malondialdehyde and improve superoxide dismutase activity of red blood cell in isolated rabbit hearts. In the experiment with coronary artery occlusion of rats, TMZ 4mg/kg administered intravenously could also inhibit arrhythmias induced by ischemia and reperfusion. The mechanism may be related to the depression of lipid peroxidation reaction.