Abstract: Unconsolidated soft soils and dredger which are newly deposited near the seashore and their properties are weak. The laboratory tests on some samples shows it is feasible to dredger hardened by adding, cement and lime. Triaxial-shear test, high-pressure consolidation test, direct-shear test and micro-penetrating test indicate that the best mixing ratio is 15 % for cement, and the more mixing ratio is, the higher strength for lime.