Provided are a prelithiation method of a silicon-based active material, the prelithiation method including step S1 of immersing the silicon-based active material in a prelithiation solution including an organic solvent and a lithium-hydrocarbon molecule complex, step S2 of obtaining a powder by washing the silicon-based active material with the organic solvent and drying the silicon-based active material, and step S3 of performing a heat treatment on the powder at a temperature of 400° C. to 800° C. in an inert gas atmosphere, and a silicon-based active material prelithiated by the method.