Aim To compare cardioprotection effects between carvedilol and metoprolol in canine late reperfusion of acute myocardial infarction.Methods Eighteen anesthetized dogs were randomly divided into three groups: late reperfusion group(LR,n=6),late reperfusion after metoprolol treatment group(LR+M,n=6),and late reperfusion after carvedilol treatment group(LR+C,n=6),respectively orally giving physiological saline,metoprolol(1 mg?kg~(-1)?d~(-1)),and carvedilol(1 mg?kg~(-1)?d~(-1)) for seven days,and then late reperfusion of acute myocardial infarction model was made by ligating the coronary for 6 h,followed by reperfusion for 6 h.SOD,GR activity and MDA content of infarction brim myocardium were detected by colorimetry,Fas/FasL were detected by immunohistochemistry,apoptosis index(AI) were detected by TUNEL.Results Compared with LR,Myocardial MDA content in LR+C was decreased,and SOD and GR activities were significantly higher,but LR+M did not change.The expression of Fas/FasL and apoptosis index were significantly lowered in LR+M and LR+C,especially in LR+C.Conclusion Carvedilol and metoprolol have cardioprotection on late reperfusion of acute myocardial infarction,and carvedilol is superior to metoprolol and the pharmacological effects may due to its antioxidant effect.