The invention relates to a water-damping bottom-supported bracket for an underwater vehicle. The water-damping bottom-supported bracket comprises a pair of bottom-supported brackets, wherein both the bottom-supported brackets are provided with a group of bracket guide pipes; a plurality of overflowing holes are arranged along the peripheries of all the bracket guide pipes; sliding rods capable of sliding are arranged in the bracket guide pipes; the ends of the sliding rods, extending out of the bracket guide pipes, are connected at the bottom part of the underwater vehicle; the ends of the sliding rods, extending into the bracket guide pipes, are provided with limiting blocks; rubber gaskets are also arranged at the bottom parts of the limiting blocks; limiting sliding rings for preventing the sliding rods from exceeding the sliding stroke are also arranged at the connection positions of the sliding rods and the inner rings of the bracket guide pipes. The water-damping bottom-supported bracket has the advantages that the structure is simple, the use is convenient, and the adaptability to assembly is strong; the traditional rigid bottom-supported bracket is replaced, the impact force when the underwater vehicle is supported at the bottom is reduced, the damage of a shell and outboard equipment when in bottom supporting is reduced, the influence of bottom-supported absorbing force on the underwater vehicle is effectively avoided and the comfort for personnel in the underwater vehicle is improved.