The invention provides a sliding plate supporting seat. The sliding plate supporting seat comprises an upper connecting plate, an outer ring plate, a rubber supporting seat, a high polymer material plate, a stainless steel mirror plate and a lower connecting plate. A vertical bearing system is composed of the upper connecting plate, the rubber supporting seat, the high polymer material plate, thestainless steel mirror plate and the lower connecting plate. In the vertical force transmission process, the rubber supporting seat does not bear the function of a horizontal load; compared with an ordinary elastic sliding plate supporting seat, the rubber supporting seat cannot be cut off under the earthquake action due to the too large friction coefficient of a lower sliding plate; and a horizontal bearing system is composed of the upper connecting plate, the outer ring plate, a lower sealing plate of the rubber supporting seat, the high polymer material plate, the stainless steel mirror plate and the lower connecting plate, and horizontal force is transmitted step by step through the components during an earthquake, so that when the horizontal force reaches the high polymer material plate, relative sliding between the high polymer material plate and the stainless steel mirror plate happens, and the earthquake effect on an upper structure is reduced through friction energy consumption.