In order to address the issues of low initial Coulombic efficiency of SiO_x-C composite anode due to the formation of solid electrolyte interphase, irreversible conversion reaction, and large volume change, the prelithiation method using metal lithium has been employed as one of effective solutions. However, violent side reactions with liquid electrolyte for prelithiation lead to low prelithiation efficiency and induce poor interface between the SiO_x-C electrode and liquid electrolyte. Here, a new prelithiation method with so called solid-state corrosion of lithium is developed. By replacing liquid electrolyte with solid-state electrolyte of carbon-incorporated lithium phosphorus oxynitride (LiCPON), not only various side reactions associated with metal lithium are avoided, but also the perfect interface is achieved from the decomposition products of LiCPON. The successful implementation of solid-state corrosion prelithiation can be confirmed by changes in optical image, scanning electron microscopy, and X-ray diffraction. Compared with pristine electrode, the initial Coulombic efficiency of the prelithiated electrode using solid electrolyte can be increased by about 10%, reaching 98.6% in half cell and 88.9% in full cell. Compared with prelithiated electrode using liquid electrolyte, the prelithiation efficiency of the prelithiated anode with solid-state corrosion can be increased from 25.7% to 82.8%. Solid-state corrosion of lithium is expected to become a useful method for prelithiation of SiO_x-C composite electrode with high initial Coulombic efficiency and large prelithiation efficiency.