The invention discloses a graphene composite cable material and a method for preparing the same. The graphene composite cable material is made of polyimide emulsion, modified montmorillonite, high-density polyethylene, polyfuran dioctyl phthalate glycol ester, silane coupling agents KH-550, sulfur powder, titanium diboride, glass fibers, citrate, graphene, choline alfoscerate, di-(3, 4-dimethyl) benzyl sorbitol, dispersing agents and anti-aging agents. The method includes processes of fitting grinding, spray-drying, acidifying, mixing, ultrasonic treatment, extrusion, stretching, heat setting and the like. The graphene composite cable material and the method have the advantages that requirements of high-voltage and direct-current power transmission cables on the hardness and the toughness of the graphene composite cable material prepared by the aid of the method can be met, the graphene composite cable material is good in environmental protection performance and low in integral cost, accordingly, industrial requirements can be met, and the graphene composite cable material and the method have excellent application prospects.