The invention relates to the structural design of a barreled water bottle, and aims at providing a bottle bottom structure of the barreled water bottle. A body of a bottle bottom of the bottle bottom structure is in a semispherical shape or a curved surface shape similar to the semispherical shape. A center boss protruding towards the inner side sphere center is arranged at the center position. Multiple supporting legs protruding outwards are arranged on the body of the bottle bottom, wherein the top ends are located on the same horizontal plane, and the horizontal plane is perpendicular to the vertical axis of the barreled water bottle. A groove indented inwards is formed between every two adjacent supporting legs. The supporting legs and the grooves are alternate. The grooves extend towards the center boss from the periphery of the bottle bottom and are formed in a radial manner in the radial direction. The bottle bottom structure has the beneficial effects that after a bottle body is filled with nitrogen and pressed, the bottle body can stand stably due to the bottle bottom, and outward-protruding deformation of the bottle bottom can be effectively restrained. Reinforcing ribs extend to the positions close to the center of the bottle bottom all the way from the periphery of the bottle bottom, supporting points are reinforced, and a good supporting effect is achieved for the whole bottle body. Under the condition that the use requirement is met, more PET raw materials can be saved, and the bottle bottom structure can be applied to a large barrel bottle with the volume within 50 L.