Abstract: 【Objective】To reduce the settlement of the foundations in dredged sea silt, light treatment was adopted, through preparing sea silt-construction waste mixed lightweight soil with the characteristics of lightweight and high-strength. 【Method】The final mixture took dredged sea silt as raw soil, cement as curing agent and light construction waste as light material. The optimum mixture ratio was determined by examining the influence of the compositions of the mixture on the density and strength of the final material. Meanwhile, taking the lightweight, high-strength, and economic requirements of the final material into consideration, the ideal ratio for mixing lightweight soil to cement and the water stability of the resulting mixture were determined.【Results】The cement component had very little influence on the density of the final material. The lightweight construction waste component had a more significant effect on the density of the mixture, which decreased with increasing amounts of lightweight construction waste. Both the cement and the lightweight construction waste components influenced the unconfined compression strength of the mixture. When the amount of the lightweight construction waste component was kept constant, the strength of the mixture increased with increasing amount of cement. Conversely, the strength of the mixture increased initially with increasing amount of the lightweight construction waste and then decreased, leading to the peak strength value. 【Conclusion】Different raw soil, curing agent and lightweight materials all affected the physical and mechanical properties of the mixture. In practical engineering applications, if the composition of the mixture changed, it is necessary to verify the practical applicability of this formula.