Due to the special process of alumina production, the resulting red mud has characteristics such as high water content, high plasticity, low strength, and low bearing capacity. Red mud is not suitable for direct use as road fill material and must undergo modification and solidification treatment. From the perspective of modifying and solidifying road base fill materials, research is conducted on the selection of modified materials, methods, mixing ratios, and control of road use conditions. Through a large number of indoor experiments, research is conducted on the modification and solidification treatment methods, action mechanisms, and effect evaluation of red mud, and an optimized red mud modification and solidification system is proposed; the solidification mechanism is revealed through microscopic structure analysis.