The invention discloses a graphene material for a lithium battery and a preparation method thereof. The graphene material for the lithium battery contains raw materials of potassium hydroxide, active carbon, Ni-Co lithium manganate, graphene oxide, sodium hydroxide, sodium borohydride, lithium nitrate, triethylene tetramine, N, N-diethylhydroxylamine and N, N-diethyl ethylene diamine. The graphene material for the lithium battery, disclosed by the invention, has the advantages that the mechanical property is excellent, the internal resistance of the battery is reduced, the service life of the battery is prolonged, the heat-conducting property is excellent, the raw materials are cheap, the operation is simple, the electrical conductivity is excellent, the battery is rapidly and fully charged within 5-9 minutes, large-current discharging performance and low temperature performance of the battery are improved, the stability of the battery is good, the battery can be charged and discharged for 400-500 times in circulation, the battery capacity reaches 700-900 mAh, the process is simple and easy to operate, the product quality and the product yield are stable and easy to control, and the graphene material can be widely produced and continuously replace the existing materials.