The invention discloses a door-body locking device for a flood-proof protective door. The flood-proof protective door specifically comprises a hand wheel, a gear transmission pair, a hydraulic motor,a guide-rod installing base, a worm-wheel and worm speed reducer, a guide rod, a connecting-rod connecting bracket, a connecting rod, a locking-tongue rotating base, a rotary pin and a locking tongue.The door-body locking device is characterized in that the guide rod is driven to move up and down by the worm-wheel and worm speed reducer, and further the locking tongue is driven to rotate into a rectangular locking hole of a door frame so as to finish the locking action of the device. The door-body locking device disclosed by the invention has the advantages of simple structure, fast locking speed, compression resistance and sealing performance after locking, convenience in operation and high safety, and has the characteristics of a purely-manual operation mode and a completely-automatic operation mode, so that the engineering application value is good.