The invention discloses a heat-stable and high-abrasion-resistant polycrystalline diamond composite sheet. The composite sheet comprises a cemented carbide substrate and a polycrystalline diamond layer composited on the cemented carbide substrate through sintering, wherein the polycrystalline diamond layer is made of a single layer of diamond powder; and the single layer of diamond powder is composed of, by weight, 5-8% of 20-30 micron coarse powder, 87-94% of 10-20 micron medium powder and 1-5% of 2-4 micron fine powder. According to the heat-stable and high-abrasion-resistant polycrystallinediamond composite sheet, the thermal stability and abrasion resistance of the composite sheet can be improved.