The invention relates to a layer casting molded graphene-nonmetal-metal composite material and a preparation method thereof. The preparation method of the layer casting molded graphene-nonmetal-metal composite material comprises the following steps of carrying out mixed grinding and shearing on a graphene quantum dot and/or a microchip and a nonmetal-metal substance under ultrasonic action, drying an obtained mixture, then subjecting the mixture to laser treatment, carrying out quenching and refinement, and promoting molecular rearrangement and grafting fusion. The layer casting molded graphene-nonmetal-metal composite material prepared by the preparation method has advantageous performance of being high in hardness, high in strength and low in electrical resistivity and being easily processed and used, can be widely applied to the field of material processing of tooth implantation, super electric drills and the like, the field of energy storage materials for batteries and super capacitors, the field of catalyst materials, the field of heat radiating materials, the field of medicine, the field of coating materials, the field of electrically conductive ink, the field of photoelectric and sensor materials, the field related to biology, and the like.