The invention discloses a graphene battery, which comprises a front electrode, a graphene/nano-silicon composite electrode sheet, a semiconductor and a back electrode, wherein the front electrode is symmetrically arranged at the upper end of the graphene/nano-silicon composite electrode sheet, and the semiconductor is arranged between the graphene/nano-silicon composite electrode sheet and the back electrode. The invention prepares graphene oxide/nano silicon material by mixing graphene oxide and nano silicon in liquid phase, and then prepares graphene/nano silicon composite material through high-temperature thermal reduction. The composite material prepared by this method has few defects and good battery stability, which is conducive to promoting the practical application of graphene/nano-silicon composite materials in lithium ion batteries.