The utility model relates to a steel double-leaf flood-proof door which comprises a door frame, door leaves, an upper bolt clamping mechanism and a lower bolt clamping mechanism, the upper bolt clamping mechanism and the lower bolt clamping mechanism are arranged on the door leaves, a lower doorsill of the door frame is buried in a terrace, and the upper surface of the door frame is flush with the terrace; the upper part of the lower doorsill is provided with a plurality of openings for inserting bolts; the upper and lower bolt clamping mechanism comprises a bolt, a movable sinking water retaining block which moves up and down synchronously with the bolt is fixedly arranged on the bolt, the movable sinking water retaining block is in an L shape, the bottom face of the movable sinking water retaining block can cover the upper surface of the lower doorsill, and a rubber sealing piece is arranged on the side face of the movable sinking water retaining block to be attached to the door leaf. The lower doorsill is pre-buried in the terrace and kept on the terrace, when the plug pin is downwards inserted into the lower doorsill, the L-shaped movable sinking water retaining block moves downwards together, the bottom face of the L-shaped movable sinking water retaining block presses the lower doorsill, meanwhile, the side face of the L-shaped movable sinking water retaining block blocks a door crack in the bottom of the door leaf, and the good sealing and flood preventing functions are achieved.