Abstract: Due to the high organic content of dredged soil, its ability to adsorb various contaminants such as heavy metals warranted an investigation of its use in clay liner of landfill. A combination of silty soil with dredged soil to enhance the geoenvironmental properties was investigated by series of laboratory tests involving adsorptivity and diffusibility which were mainly cared in clay liner of landfill. It was shown that the mixed soil (dredged soil and silty clay) had much larger adsorption capacity for Cu2+ than silty clay, and its strong adsorption capacity for Cu2+ resulted in a barrier with the mixed soil having a much less diffusion coefficient than silty clay.