The effects of hydrogen-rich water on oxidative stress via the Nrf2/ARE signaling pathway were studied in rats with myocardial ischemia-reperfusion injury (MIRI). Sixty rats were randomly divided into a hydrogen-rich water group and a control group, with 30 rats in each group. The two groups were randomly divided into three groups: pre-ischemic period, ischemic period and reperfusion period. After the heart was removed, it was fixed in a Langendorff device and perfused with an oxygen-balanced 37 degrees C perfusate. The control group was perfused with Kreb's-Ringers (K-R) solution, and the hydrogen-rich water group was perfused with K-R solution + hydrogen-rich water. The levels of mRNA and protein of Nrf2, NQO1, HO-1 and SOD-1 in cardiomyocytes were detected by RT-qPCR, immunohistochemistry (IHC) and Western blot analysis. SOD activity and MDA content were determined. Hydrogen-rich water increased the activation of the Nrf2/ARE signaling pathway, and the levels of mRNA and protein Nrf2, NQO1, HO-1 and SOD-1 were significantly increased (P < 0.05) in the ischemia-reperfusion period compared with the ischemic period. In the control group, the levels of mRNA and protein of Nrf2, NQO1, HO-1 and SOD-1 were significantly decreased (P < 0.05) in the ischemia-reperfusion period compared with the ischemic period. Compared with the ischemic period, the ischemia-reperfusion phase showed significantly increased SOD activity and significantly decreased MDA content in the hydrogen-rich water group, while SOD activity was significantly decreased, and MDA content was significantly increased in the control group (P < 0.05). Hydrogen-rich water can activate the Nrf2/ARE signaling pathway, alleviate ischemia-reperfusion injury in isolated rat hearts and reduce the oxidative stress level of myocardial tissue.