Abstract: In order to solve the problems of poor permeability and long drainage consolidation time of dredged sludge, flocculation-vacuum preloading method is often used to treat the existing foundation, and a foundation treatment method of grouting flocculation combined with vacuum preloading is proposed. The indoor model test of soil with different initial water content and dredging silt was carried out by controlling different lime content, and the changes of pore water pressure, displacement and settlement were monitored. After the test, the pH value, total salt content of soil, soil water content and vane shear strength were detected. The optimal lime content of grouting flocculation-vacuum preloading method to strengthen dredged sludge with different initial water content considering soil salinization is obtained. Then the effectiveness of grouting flocculation-vacuum preloading method is further verified by the field application of Longwan Phase II coastal wetland restoration project. The results of this study can provide reference for similar practical engineering applications.