The invention discloses a method of producing an interlayer insulation layer for multi-layer polycrystalline silicon. The method comprises steps that 1) a polycrystalline silicon oxidation layer is formed on the surface of the polycrystalline silicone;2) a restoration layer is deposited on an upper side surface of a silicon nitride substrate, and the restoration layer is used to cover the exposed area of the polycrystalline silicon oxidation layer and the exposed area of the upper side surface of the silicon nitride substrate; 3) primary etching is carried out, and the restoration layer is etched, and after the etching, the restoration layer having a certain thickness remains on the surface of the exposed areas; 4) secondary etching is carried out, and then the restoration layer on the surfaces of the exposed areas is etched, and after the etching, the restoration layer remains on the root part of the polycrystalline silicon; the polycrystalline silicon oxidation layer and the restoration layer remaining on the root part of the polycrystalline silicon are used to form an interlayer insulation layer. The method of producing the interlayer insulation layer for the multi-layer polycrystalline silicon is advantageous in that the growth defect of the polycrystalline silicon oxidation layer is restored, and therefore the interlayer insulation layer meeting a quality demand is acquired.