A method for relieving a hole defect of a gate is disclosed, which includes: providing a substrate; forming a polysilicon layer over the substrate; forming a sacrificial oxide layer over a surface, that faces away from the substrate, of the polysilicon layer; forming a patterned photoresist layer over the sacrificial oxide layer; performing ion implantation by using the patterned photoresist layer as a mask; removing the patterned photoresist layer and the sacrificial oxide layer. In the method, before ion implantation, an oxide layer is formed over the surface of the gate, and is used to reduce affinity of the polysilicon and the photoresist layer. Afterwards, the floating gate is cleaned for many times, and hydrofluoric acid of an appropriate amount is added, so as to completely remove the photoresist layer and other residues while cleaning off the sacrificial oxide layer.