NOVELTY - Preparing three-dimensional flocculent graphene substrate material comprises dispersing expanded graphite in water, adding aqueous dispersion of polystyrene beads, and ultrasonicating; suction filtering the expanded graphite-polystyrene composite dispersion with foamed nickel, drying, placing the expanded graphite-polystyrene loaded foamed nickel in hydrazine hydrate and aqueous ammonia mixed solution, reacting to obtain graphene-polystyrene loaded foamed nickel substrate material; and heating, and insulating.    USE - The three-dimensional flocculent graphene substrate material with titania, manganese dioxide, iron oxide, cobalt oxide or tricobalt tetraoxide compound is useful in supercapacitors, lithium-ion batteries or photocatalysis (claimed).    ADVANTAGE - The three-dimensional flocculent graphene substrate material has good electrical conductivity, greatly reduces internal resistance of a capacitor, and increases performance of the capacitor electrode active material, and is suitable for large-scale production of graphene.    DETAILED DESCRIPTION - Preparing three-dimensional flocculent graphene substrate material comprises (i) adding graphite oxide in a crucible, placing the crucible in a muffle furnace, heating to 900-1100 degrees C at the heating rate of 5-20 degrees C/minute, then insulating the muffle furnace for 0.5-2 minutes, and removing the crucible to obtain expanded graphite; (ii) dispersing 10 ~ 20 mg expanded graphite in 10-30 ml water, adding 200-800 mu l aqueous dispersion of polystyrene beads, and ultrasonicating for 1-4 hours; (iii) suction filtering the expanded graphite-polystyrene composite dispersion with foamed nickel at the rate of 2-4 l/second, drying at 40-60 degrees C for 12-18 hours, placing the expanded graphite-polystyrene loaded foamed nickel in hydrazine hydrate and aqueous ammonia mixed solution, where the volume ratio of hydrazine hydrate and aqueous ammonia is 1:5-1:10, reacting at 90-95 degrees C for 1-3 hours, taking out and washing with deionized water and impregnating for 3-5 times, and drying at 40-60 degrees C for 12-18 hours to obtain graphene-polystyrene loaded foamed nickel substrate material; and (iv) placing the graphene-polystyrene loaded foamed nickel substrate material in a tubular furnace, under vacuum heating to 450-500 degrees C at heating rate of 1-2 degrees C/minute, and insulating for 1-2 hours.