With the in-depth investigation of cardiac fibrosis, oxidative stress (OS) has been recognized as a significant pathophysiological pathway involved in cardiac remodeling and progression. OS is a condition characterized by the disruption of equilibrium between reactive oxygen species (ROS) produced by the organism and the antioxidant defense system, resulting in adverse effects on the structure and function of the heart. The accumulation of reactive substances beyond cellular thresholds disrupts the normal physiology of both cardiomyocytes and non-cardiomyocytes, leading to OS, inflammation, hypertrophy, and cardiac fibrosis. Furthermore, cardiac OS also modulates several crucial genes involved in maintaining cellular homeostasis, including those associated with mitochondrial biogenesis, injury, and antioxidant defense, which are inevitably associated with concurrent epigenetic changes. Multiple studies have demonstrated the crucial role of epigenetic modifications in regulating cardiac OS. Consequently, modulating OS through targeted epigenetic modifications emerges as a potentially promising therapeutic strategy for managing cardiac fibrosis. This article provides a new review of current research on this subject and proposes that epigenetics may improve OS-induced cardiac fibrosis.