Abstract: The Iron-Chromium Redox Flow Battery (ICRFB) has become one of the research hotspots in the field of large-scale long-duration energy storage due to its advantages such as high safety, long cycle life, strong design flexibility, and low maintenance cost. As the core component of the battery and the main site for electrochemical reactions, the structure and performance of the electrode material play a decisive role in the overall battery efficiency. Compared with metal-based and composite electrodes, carbon-based electrodes dominate in ICRFB due to their advantages such as low cost, three-dimensional conductive network, and excellent stability. However, problems such as insufficient active sites, limited specific surface area, and poor electrolyte wettability severely restrict the electrochemical performance of the battery. This review focuses on the multi-scale modification of carbon electrodes: optimizing the reaction kinetics through the regulation of surface functional groups (such as hydroxyl groups and carboxyl groups), and improving the catalytic activity of the electrodes by loading metals/metal compounds/non-metallic materials, etc., to achieve an increase in current efficiency. Existing research still lacks a systematic analysis of the modification mechanisms (such as the structure-activity relationship between functional groups and active sites, and the charge transfer path at the catalyst interface). From the perspective of surface engineering, this review further conducts an in-depth analysis of the enhancement mechanisms of different modification strategies and introduces the relevant quantitative relationship models constructed by high-throughput calculations to link the modification strategies with performance improvement. This article can provide a theoretical basis for breaking through the trade-off bottleneck of "activity-stability-cost" of carbon electrodes and has important guiding significance for promoting the development of key materials for the next generation of redox flow batteries.