Reinforcing structure utilizing three-side wall cantilever beam lower support

The utility model relates to the technical field of building construction, and discloses a lower support reinforcing structure of a cantilever beam utilizing three walls, which is arranged between opposite shear walls on two sides and a U-shaped structure formed by a cantilever surface on one side, and comprises a support beam I arranged on the cantilever surface through a reinforcing piece I, mounting ports which are correspondingly communicated with each other are formed in the shear walls on the two opposite sides, a supporting beam II is arranged between the mounting ports on the two sides, the supporting beam II is perpendicular to the supporting beam I, the end, extending out of the cantilever face, of the supporting beam I extends to the outer side of the U-shaped structure and is located above the supporting beam II, and the supporting beam I and the supporting beam II are connected through a reinforcing piece II. The cantilever face and the shear walls on the two sides of the cantilever face jointly