Flavor stability has been regarded as a major long-standing challenge for the beer industry, whereas reactive oxygen species (ROS) have been confirmed as the core factors by which beer aging is driven. Comprehensive elucidation of ROS metabolic networks and antioxidant defense mechanisms is deemed essential for aging pathways to be clarified and long-term preservation strategies to be designed. In this study, diverse ROS generation pathways and their metabolic transformation dynamics over the entire beer chain from raw materials and brewing to storage are systematically summarized. The molecular mechanisms through which oxidative deterioration of lipids, proteins and polyphenols is induced by ROS, followed by the formation of key aging flavor compounds including trans-2-nonenal, are thoroughly analyzed. On this basis, the endogenous synergistic antioxidant network constituted by phenolic compounds, sulfur dioxide, Maillard reaction products and antioxidant enzyme systems is reviewed. Furthermore, recent advances in antioxidant regulation strategies are critically evaluated from the dimensions of raw material selection, low-oxygen processing, exogenous supplementation, packaging improvement and biotechnological intervention. Literature data are integrated to compare the inhibitory efficiencies of different strategies on aging indicators. Finally, it is suggested that future investigations should be concentrated on technologies for spatiotemporal dynamic monitoring of ROS, precise synergistic mechanisms of multicomponent antioxidants, and the development of intelligent anti-aging yeasts using synthetic biology. This review aims to provide systematic theoretical foundations and technical references for the targeted and long?term stabilization of beer flavor.