The invention relates to a movable overwater slurry treatment platform. The movable overwater slurry treatment platform comprises a wharf boat, a slurry treatment system and a slurry dumping boat, wherein the wharf boat floats on water; the slurry treatment system is arranged on the wharf boat, the slurry treatment system communicates with a slurry bin of a shield machine through a slurry discharging pipe and a slurry conveying pipe, slurry in the slurry bin is discharged and conveyed into the slurry treatment system to be treated through the slurry discharging pipe, and the slurry obtained after treatment is conveyed to the shield machine through the slurry conveying pipe; and the slurry dumping boat floats on the water and communicates with the slurry treatment system, and the abandonedslurry produced in the process of slurry treatment is discharged and conveyed into the slurry dumping boat through the slurry treatment system and conveyed out through the slurry dumping boat. The movable overwater slurry treatment platform effectively integrates the slurry treatment system on land with the slurry dumping boat in water, does not occupy a construction site, reduces site requirements of slurry shield construction, and is suitable for engineering of a narrow site.