The invention provides a preparation method of
graphene. The method comprises the following steps: (A) pretreating biologic materials to obtain the pretreated biologic materials, wherein the biologic materials comprise one or several kinds of
forestry and agricultural residues, tea leaves and seaweed plants; (B) mixing
metal catalysts, solvents and the biologic materials pretreated in the step (A) to obtain the biologic materials loaded with the catalysts; (C) mixing pore forming agents and the biologic materials which are obtained in the step (B) and loaded with the catalysts, and heating for 0.5 to 10 hours under the temperature of 700-1200 DEG C to obtain the
graphene. The preparation method for the
graphene, provided by the invention, has no
pollution to environment, the biologic materials are used as carbon sources, the cost of the raw materials of the carbon sources is low, and the raw materials are easy to obtain, so that the problems that the cost of existing carbon sources is high, and existing carbon sources are not beneficial to the large-scale industrialization are solved.