Method for preparing graphene by using eutectic graphite

The present invention relates to a method for preparing graphene by using eutectic graphite. According to the present invention, the method for preparing graphene by using eutectic graphite comprises: a first step of preparing a sintered body, comprising diamond and unreacted graphite, by sintering a mixture powder comprising a metal and graphite; a second step of converting, by dipping the sintered body in a strong acid containing potassium permanganate (KMnO 4 ) and carrying out electrolysis on the same into a mixture comprising diamond and graphite; a third step of stripping graphite within the mixture; a fourth step of recovering stripped graphene oxide; and a fifth step of reducing the recovered graphene oxide. According to the present invention, a process can be reduced by simultaneously carrying out a graphite pre-treatment step of in a process for preparing graphene and a process for preparing diamond, and thus there are effects of reducing reagents costs, which are required for pre-treatment, and processing costs.