The invention relates to the technical field of ship manhole sealing, and discloses a marine manhole sealing protection device, a manhole cover plate base is mounted above a manhole, and a cover plate support is arranged at the bottom of the base. A shell is arranged on the base, and a driving mechanism is arranged in the shell. The mechanism comprises a lower plate, a vertical plate, an upper plate, a
hydraulic motor, a belt wheel I, a belt wheel II, a screw rod, a nut seat, a connecting seat, a clamping sleeve, a lifting sleeve, a fixed
pipe seat, a sliding sleeve and a pressing rod. The
hydraulic motor drives the first belt wheel, the second belt wheel is driven by the belt to rotate, the second belt wheel drives the screw to rotate, the nut seat moves along the screw, the linkage seat and the clamping sleeve move along with the screw, the lifting sleeve slides in the fixed
pipe seat, and the pressing rod ascends and descends to control the manhole cover plate. The driving mechanism achieves accurate control over the screw through a
hydraulic motor and a belt
transmission system, and then the lifting sleeve and the pressing rod are driven to do lifting motion in the vertical direction. The tedious process of traditional manual operation is simplified, and the sealing efficiency and reliability are remarkably improved.