The present invention relates to a sound-insulating and vibration-isolating rubber pad and a method for installing a sound-insulating and vibration-isolating floor using same in which lower pad protrusions can be inserted into a plurality of insertion holes formed in a lower water-proof plywood because the lower pad protrusions are formed in the center of an upper surface of a lower pad body of a sound-insulating and vibration-isolating rubber pad, so that the lower water-proof plywood and an upper pad are integrally connected above a lower pad, and a vibration-isolating function may be achieved in a stable manner because the lower pad, the lower water-proof plywood, and the upper pad are integrally connected, thereby providing a sound-insulating effect that can remarkably reduce inter-floor noise.