Genistein (Gen) exhibits strong anti-oxidative/antinitrative activity and cardioprotective effects in several models; however, its role in burn-induced myocardial injury is unknown. This study investigated the protective effect of Gen on burn-induced myocardial injury and aimed to elucidate the mechanism of protection. Mice were injected with Gen, intraperitoneally, at different dose immediately after burn injury. The expression levels of Notch-1 intracellular domain (NICD1) and hairy and enhancer of split (Hes-1) were determined by immunoblotting. Conditional Notch-RBP-J knockout mice were used to investigate the mechanisms of Gen-induced cardioprotection. Gen alleviated burn-induced myocardial injury, as shown by improved left ventricle ejection fraction, decreased serum lactate dehydrogenase and creatine kinase levels, and apoptosis. Moreover, Gen decreased expressions of inducible nitric oxide (NO) synthase and gp, reduced NO and superoxide anions production, and ameliorated their cytotoxic reaction product, peroxynitrite. More importantly, Gen significantly up-regulated the expression of NICD1 and Hes1 after burn injury. In addition, genetic knockout of Notch1 not only blocked the cardioprotection of Gen but also markedly attenuated Gen-induced anti-oxidative/antinitrative effect. These results demonstrate, for the first time, that Gen treatment attenuates burn-induced myocardial injury via the Notch1 mediated suppression of oxidative/nitrative stress.