Abstract: The hydraulic fill dredged from rivers and lakes is generally characterized by high water content, large fluidity, and greater pollution. The sand-free vacuum preloading method has a remarkable effect in consolidating and hardening the hydraulic fill, and improving its strength and bearing capacity. Due to the influences of the annular channel and the sedimentation separation, there are some differences between the foundation settlement and the change of the excess pore water pressure in the different areas of the same mud pit. This method performs an important purification function in barrier, filtration and adsorption of the organic pollutants. After the stacking and precipitation, the negative pressure suction, the tailwater precipitation, the filtration and adsorption of the aquatic plant, the content of organic matter and total phosphorus (TP) are decreased significantly, and the pollution index P is reduced from 0.8~1.0 to 0.7, which basically meets the requirements of the class Ⅲ water quality standard of the surface water. After consolidation, the content of organic matter, total nitrogen and total phosphorus in the soil had decreased greatly, and the organic pollution index OI is improved by one grade. The content of the heavy metal element in the soil meets the class Ⅲ environment quality standard for soils, and the leaching toxicity of the heavy metals is low, thus producing no pollution to the surface water. The calculation results show that the heavy metals pollution degree is slight.