The invention provides a movable ship plate maintenance floating dock. The floating dock is used for maintaining a ship bottom plate of water equipment. The floating dock is characterized by comprising a floating dock body, wherein the floating dock body is provided with a void cabin, an opening is formed in the upper portion of the void cabin, a first connecting pipe and a second connecting pipeare arranged on a cabin body of the void cabin, and the first connecting pipe and the second connecting pipe communicate with the void cabin correspondingly and are both provided with valves; and thefirst connecting pipe is used for discharging water in the void cabin, and the second connecting pipe is used for connecting with a compressor to inject gas into the void cabin. The compressor injectsthe gas into the void cabin through the second connecting pipe, then the water in the void cabin is discharged from the first connecting pipe, and the floating dock body is attached to the ship bottom plate under the pressure of the water to form a closed space, so that the ship bottom plate to be maintained can be maintained.