Abstract: The masculinization caused by environmental stress, such as high temperatures, has severely impacted aquaculture worldwide, but the mechanisms and rescue methods have not yet been reported. Producing XX genotypic all-female yellow catfish is an important approach for conducting their genetic improvement, however, high water temperatures and other environmental stresses can induce masculinization, which has seriously affected the breeding efficiency based on all-female populations. In the present study, XX genotypic yellow catfish were used as experimental materials and treated with high temperature (HT), hydrogen peroxide (H₂O₂), and HT-H₂O₂ dual stress. Under HT-H₂O₂ treatment, emodin (E, with antioxidant function) was used to rescue masculinization. The experiment set up three masculinization induction treatment groups, i.e. HT group (33.5℃), HP group (1 μmol/L H₂O₂), TP group (33.5℃+1 μmol/L H₂O₂), and a rescue group, TPE group (33.5℃+1 μmol/L H2O2+300 mg/kg E mixed with feed), which were treated during the period of sex differentiation (12—80 DPH). The results showed that the masculinization rates in the HT, HP, and TP groups were 23.7%, 13.9%, and 41.6%, respectively. In comparison, the masculinization rate in the TPE group was 6.9%, all with intersex gonads, indicating that emodin treatment significantly reduced stress-induced masculinization. The oxidative stress indicators showed that CAT and SOD activities and MDA content of the pseudo-male increased significantly compared to females (P<0.05). The GSH-Px activity in the TPE group increased significantly compared to the stress group, suggesting that the addition of emodin improved antioxidant capacity and rescued masculinization. Furthermore, field experiments in pond-reared XX all-female stocks demonstrated that feeding fish 500 mg/kg of emodin resulted in 96.4% of individuals exhibiting normal ovarian development, while only 3.6% developed into pseudo-males. This study preliminarily clarifies that oxidative stress is involved in environmental stress-induced masculinization, and emodin with antioxidant function can rescue the masculinization induced by environmental stress. The results provide an important basis for a deeper understanding of sex differentiation plasticity and offer a potential strategy for sex reversal rescue in fish.