This study aims to address the issues of instability and excessive deformation in high embankments constructed on soft clayey foundations, by proposing a composite reinforcement strategy that integrates pressed riprap, geogrid reinforcement, and replacement filling. A finite element model was developed to simulate the mechanical response of the composite reinforcement measures under varying filling heights (ranging from 8 to 16 m). The analysis focused on evaluating the effects of these measures on the embankment’s stability, failure mode, and ultimate filling height. The results demonstrate that the composite reinforcement structure significantly enhances embankment stability compared to pressed riprap alone. The combination of pressed riprap, geogrid reinforcement, and replacement filling exhibited the best performance, achieving a safety factor of 2.01 at an embankment height of 8 m, which represents a 34% improvement over the unreinforced case. The ultimate filling height for this composite structure can reach 11.7 m (with a safety factor of 1.4). This study provides a theoretical foundation and parameter references for the design of composite reinforcement systems for high embankments on soft foundations.