Abstract: Due to human activities, the original water-sediment balance in the southern sea area of Xiang’an, Xiamen has been disrupted, triggering a series of problems including coastal siltation, weakened nearshore hydrodynamic conditions and beach muddying. Taking the middle and eastern sections on the west side of the north bank of Dadeng Bridge as the research area, this paper conducts research on multi-parameter collaborative optimization key technologies for beach restoration on muddy coasts. Dynamic geomorphology suitability evaluation is carried out by combining historical nautical charts and field measured data. The results reveal that the annual average significant wave height in this area is merely 0.1-0.3 m, so auxiliary nearshore dredging works are required to improve hydrodynamic conditions. Three restoration layout schemes are designed focusing on three core parameters, namely the layout of sand-retaining dikes, dredging bottom elevation and berm elevation. Joint numerical simulations using SWAN, NEMOS and XBeach models are implemented for 10-year long-term shoreline evolution and 50-year return period extreme storm conditions to quantitatively compare the alongshore sediment transport, shoreline erosion-siltation, and muddying inhibition effects of different schemes. The results indicate that Layout 3 achieves the optimal comprehensive performance: the berm elevation is optimized to 3.8-4.3 m, and the length of sand-retaining dikes is reduced by 18 m. After 10 years of restoration, the maximum shoreline erosion and siltation of the middle section reach 25 m and 5 m, respectively, while the maximum erosion and siltation of the eastern section are less than 20 m and 3 m. The annual total beach erosion-siltation volume is controlled within 9 000 m³, and the shoreline reaches dynamic equilibrium in the 5th year after restoration. Dredging to a unified bottom elevation of −4.2 m significantly increases the tidal prism and nearshore wave height of the sea area, lowering the elevation of the sand-mud boundary from the original 0.2 m to −0.8 m and effectively restraining the muddying trend. Under the 50-year return period extreme storm condition, the outer edge of the berm only retreats by approximately 1 m after 12 h of continuous wave action, and the sediment transported transversely during storms can naturally back-silt under normal wave conditions, demonstrating controllable overall shoreline stability. The research outcomes can provide quantitative technical basis and scheme references for similar muddy coastal beach restoration projects in China.