The utility model belongs to the technical field of the building, especially, relate to a low concave project under construction anti -flooding water structure, include the baffle, be located the L type ear wall of baffle both sides to and with the support system of baffle with horizontal earth's surface fixed connection, the baffle comprises a plurality of baffle units, and there are two the support ribs and baffle unit back fixed connection that intersect along the diagonal in the baffle unit back, and support rib central point puts to weld has a fixed hinge fishplate bar, the fixed hinge fishplate bar welds the three corner brace boards that the backboard face was equipped with two parallel arrangement including welding the board, the right -angle side of three corner brace boards withweld that the board is perpendicular to be set up, all be equipped with a keyhole on every three corner brace board, be equipped with articulated activity between two keyholes and tie, articulated activity is tied and support system swing joint, the utility model has the advantages of simple structure, convenient to use.