The invention discloses a preparation method of an electrolytic solution for a graphene-based lithium-ion capacitor. According to the method, a lithium salt and ion liquid mixed system is used as an electrolyte of the electrolytic solution, and an organic solvent is used as a solvent system to prepare a novel lithium-ion capacitor electrolytic solution system with ion adsorption and ion embeddingcharacteristics. The ion embedding characteristic of lithium salt and the ion adsorption characteristic of ion liquid are utilized to realize a surface functionalization reaction and ion adsorption synergetic energy storage of graphene-based positive ions, and finally the characteristics of high specific capacity and high multiplying power of the graphene-based lithium-ion capacitor can be broughtinto play.