Objective To investigate the protective effect of myricitrin on myocardial ischemia/reperfusion injury in isolated rat hearts and its underlying mechanism. Methods Sixty SD rats were randomly divided into: (1) control group; (2) model group; (3) positive administration group (verapamil of 100 μg/L); (4) three dose groups with varying amount of myricitrin (2.5, 5, 10 mg/L). Each group included ten rats. The myocardial ischemia/reperfusion injury model was constructed using the Langendorff method. The isolated working hearts were ischemia for 30 min followed by reperfusion for 45 min after in equilibrium for 15 min. During the process, we determined myocardial hemodynamic parameters, myocardial enzyme indicators (lactate dehydrogenase (LDH), creatine kinase (CK) and aspartate aminotransferase (AST)) and antioxidative parameters (superoxide dismutase (SOD), catalase (CAT) and malondialdehyde (MDA)). Furthermore, we performed histopathological examination of left ventricles and detected the expression of apoptosis related proteins (e.g., Bcl-2, Bax, Caspase-3 and Caspase-9) by western blot. Results Compared with the model group, myricitrin could significantly improve cardiac constriction and relaxation function, decrease the levels of LDH, CK and AST in perfusate, enhance the activities of SOD and CAT, and decrease the content of MDA in myocardial tissue. The cardiac protective effect of myricitrin was further confirmed by histopathological examination. Apparently, myricitrin pretreatment restrained myocardial apoptosis as evidenced by increasing the level of Bcl-2 expression, decreasing the levels of Bax, Caspase-3 and Caspase-9 expression, and inhibiting the phosphorylation of ERK. Conclusions Myricitrin had a protective effect on myocardial ischemia/reperfusion injury. It showed ability of improving myocardial contractile function, increasing anti-oxidation ability and inhibiting apoptosis. The possible mechanism of cardiac protection of myricitrin was that the agent attenuated myocardial cell apoptosis induced by ischemia reperfusion via inhibiting ERK signaling pathway.