Pressure overload-induced cardiac remodeling and dysfunction progress to heart failure, which is mainly due to excessive oxidative stress. Hence, our study aimed to illustrate whether cardamonin, a kind of chalcone, could attenuate maladaptive cardiac changes and ameliorate cardiac insufficiency through its antioxidant mechanism. In vivo, our study revealed that cardamonin treatment could attenuate transverse aortic contraction-induced cardiac remodeling and dysfunction. Histological observations have suggested that cardamonin inhibited the occurrence of excessive cardiac oxidative stress and apoptosis. In vitro, we found that 3 treatments with angiotensin II (Ang II), hydrogen peroxide, and Nox4 overexpression in H9C2 cells markedly augmented intracellular oxidative stress as measured by superoxide dismutase, L-glutathione, and malonaldehyde. Conversely, cardamonin treatment notably alleviated oxidative stress induced by the 3 above-mentioned treatments. Furthermore, all 3 treatments resulted in increased apoptotic cell death, whereas cardamonin treatment reduced apoptosis in H9C2 cells. Moreover, cardamonin significantly abrogated the expression of Bax, apoptosis inducing factor, cytochrome c, and caspase-3 and caspase-9 and enhanced the expression of Bcl-2 and Bcl-xl. In conclusion, these findings provide a new possibility for cardamonin to alleviate pressure overload-induced heart failure.