〔Abstract〕 Objective To investigate the protective effect of cordycepin(Cor) on cardiac function in aged rats and its mechanism. Methods The aged rats were divided into Model group, Cor administration group(Cor 5, 10, 20mg/kg),and young rats were used as Control group( Control). The levels of heart rate( HR),left ventricular ejection fraction( LVEF) and fractional shortening( FS) were detected by echocardiography. The levels of creatine kinase MB( CK-MB),myohemoglobin( Mb),cardiac troponin Ⅰ( cTnI),superoxide dismutase( SOD),malondialdehyde( MDA) and lactate dehydrogenase( LDH) were detected by ELISA. The pathological morphology of heart tissue was observed by HE staining. The apoptosis of myocardial cells was observed by TUNEL staining.Western blot detected the protein expression of cysteine aspartic protease 9( Caspase 9),cleaved cysteine aspartic protease 9( cleaved Caspase 9),cysteine aspartic protease 3( Caspase 3),cleaved cysteine aspartic protease 3( cleaved Caspase 3),nuclear factor E2 related factor 2( Nrf2),phosphorylation nuclear factor E2 related factor 2( p-Nrf2),quinone oxidoreductase 1( NQO1),heme oxygenase 1( HO-1). Results Compared with the elderly model group,HR,LVEF,FS increased,CK-MB,Mb,cTnI levels decreased,MDA,LDH content decreased,SOD activity increased,cleaved Caspase 9/Caspase 9,cleaved Caspase 3/Caspase 3 expression decreased,The expressions of Nrf2,NQO1 and HO-1 were increased,and the pathological morphology of cardiac tissue and myocardial apoptosis were improved in Cor groups. Conclusion Cor can improve cardiac function of elderly rats,relieve oxidative stress response,inhibit myocardial cell apoptosis and have a certain protective effect on cardiac tissue injury in rats,and the mechanism may be related to the promotion of Nrf2/HO-1 pathway related protein expression.