The invention relates to a damping structure for reducing vibration of a transformer oil tank. The damping structure comprises two metal perforated plates arranged in an oil saving box on a transformer and located on the front side and the rear side of an iron core respectively, wherein the two metal perforated plates are parallel to two wide surfaces, and gaps are reserved between the two metal perforated plates and the inner walls of the wide surfaces of the oil saving box. The upper edges and the lower edges of the metal perforated plates are respectively flush with an upper end ring and a lower end ring of the transformer, and the metal perforated plates cover the iron core in the length direction. By adopting the damping structure for reducing the vibration of the transformer oil tank, oil flow pulsation of the transformer is decreased, the pressure distribution on the inner wall of the oil saving box of the transformer is uniform, accordingly vibration and radiation noise of the oil saving box of the transformer are reduced, the cost is low, space is saved, and the heat dissipation problem is avoided.