Buoyancy type automatic flood control door

The invention relates to a buoyancy type automatic flood control door which comprises a flood control box, the flood control box is buried under the ground of a building channel entrance and exit, a hidden groove is formed in the flood control box, guide grooves are fixedly connected to the two ends of the hidden groove, and the guide grooves are connected with an enclosing wall of a building. A flood blocking plate is slidably embedded between the two guide grooves, a supporting plate is fixedly connected to the lower side of the flood blocking plate, a floating object is arranged below the supporting plate, and a dustproof cover is hinged to the side, close to the passageway passageway, of the hidden groove through a hinge. The water guide groove can guide flood into the flood control box in advance, the supporting plate and the flood baffle can be automatically controlled to be lifted under the buoyancy action of the floating object, the flood control wall does not need to be manually combined and installe