The invention relates to an interlayer resin sheet used for laminating of PCB multilayer boards. The interlayer resin sheet comprises two layers of polypropylene rubber sheets and one layer of glass fiber cloth. The mesh number of the glass fiber cloth is 100-200. The two layers of polypropylene rubber sheets are respectively a first polypropylene rubber sheet arranged above the glass fiber cloth and a second polypropylene rubber sheet arranged below the glass fiber sheet. A first epoxy resin layer is arranged between the first polypropylene rubber sheet and the glass fiber cloth, and a second epoxy resin layer is arranged between the second polypropylene rubber sheet and the glass fiber cloth. The total thickness of the interlayer resin sheet used for the laminating of the PCB multilayer boards is 1.635-1.725 mil, the thickness of the first polypropylene rubber sheet and the thickness of the second polypropylene rubber sheet are respectively 0.762-0.847 mil. The total thickness of the first epoxy resin layer, the glass fiber cloth and the second epoxy resin layer is 0.04-0.15 mil. The interlayer resin sheet used for the laminating of the PCB multilayer boards is high in leveling property, stable in swelling-shrinkage property and low in dielectric property, and the interlayer resin sheet is suitable for the laminating of the multilayer boards so as to realize the ten-layer breakthrough of high-order interconnected printed boards.