4-tert-octylphenol (4-t-OP) is an alkylphenolic environmental endocrine disruptor extensively distributed in the environment, posing potential hazards to living organisms. Research has demonstrated that 4-t-OP induces cardiac injury and abnormalities in embryonic development, which can adversely affect heart development. The excessive production of reactive oxygen species (ROS) triggered by 4-t-OP may result in DNA damage. Hence, we hypothesized that ROS-mediated DNA damage plays a crucial role in abnormal cardiac development in zebrafish embryos exposed to 4-t-OP, while resveratrol (RSV), a common antioxidant found in natural foods, may provide protection. In this study, we exposed zebrafish embryos at 2 h post-fertilization (hpf) to various doses of 4-t-OP in combination with relevant inhibitor/agonist therapies. Using microscopy, we observed morphological alterations in the cardiac structure of zebrafish embryos at 72 hpf. The underlying molecular mechanisms were assessed through immunofluorescence, DCFH-DA probe, MitoSOX™ staining, Quantitative polymerase chain reaction, and other methods. Our findings revealed that 4-t-OP caused dose-dependent cardiac defects in zebrafish embryos. The overexpression of ROS/mitochondrial ROS (mtROS) induced by 4-t-OP was significantly reduced by the addition of RSV or the ROS inhibitor N-acetyl-L-cysteine (NAC). Furthermore, the inclusion of RSV or NAC significantly mitigated cardiac deformities, cardiac apoptosis, and DNA damage. Additionally, the apoptosis inhibitor Ac-DEVD-CHO and the Wnt/β-catenin agonist CHIR99021 decreased 4-t-OP-induced cardiac abnormalities. Moreover, the naturally occurring small molecule chemical RSV provided protection against 4-t-OP-induced heart developmental injury. This study elucidates the molecular mechanisms by which 4-t-OP induces oxidative stress, DNA damage, and cardiac defects in the heart of zebrafish larvae through the ROS/Wnt/β-catenin signaling pathway. These findings present novel molecular targets for the prevention and therapy of congenital heart disease, as well as enhance our understanding of the cardiotoxic effects of 4-t-OP.