The utility model discloses an elastic concrete plinth for supporting a large-scale steam turbine generator. A column side embedded part is pre-buried on the outer side wall of the supporting column of a frame, a post-cast concrete column head plane is arranged on the upper surface of the supporting column of the frame, the embedded part is arranged in the column head plane, a steel frame made of angle steel is pre-buried around the column head plane, and the steel frame made of the angle steel is flush with the column head plane. A supporting frame made of section steel is welded at the periphery of the column head of the supporting column of the frame, the inner side of the lower part of the supporting frame made of the section steel is welded with the steel frame made of the angle steel and the column side embedded part, and the upper part of the supporting frame made of the section steel is higher than the plane of the column head. At least four spring vibration isolators are arranged on the column head plane and in the supporting frame made of the section steel. Upper embedded steel plates are arranged on the spring vibration isolators and on the supporting frame made of the section steel, and are pre-embedded in mass reinforced concrete, and the spring vibration isolators of the supporting column of the frame are elastically connected with the mass reinforced concrete. The elastic concrete plinth solves the problems that an elastic plinth is incapable of being stressed in advance, and a concrete bottom die is difficult to be supported, therefore the reinforced concrete structure is prevented from being damaged by the resonance vibration.