NOVELTY - A composite graphene preparing method involves mixing stone powder, sodium nitrate and concentrated sulfuric acid, adding potassium permanganate and graphite powder and preparing graphene oxide slurry materials. The graphene oxide slurry material is washed and dried. The oxidized graphene is diluted, hydrated, washed and filtered. The modified graphene is dispersed. The liquid is heated with sulfur, lithium sulfide and water, washed and filtered. The paper is pressed. The film is placed in graphene composite film, filled with nitrogen gas to obtain the finished product.    USE - Method for preparing composite graphene for use as lithium battery positive material.    ADVANTAGE - The method enables preparing composite graphene with good dispersion stability, good output, high conductivity, improved energy density of lithium battery positive performance, improved power characteristics, and improved thermal conductivity, electrical conductivity and strength properties.    DETAILED DESCRIPTION - A composite graphene preparing method involves mixing stone powder, sodium nitrate and concentrated sulfuric acid in certain volume, adding potassium permanganate and graphite powder at 10 degrees C for 1.5 hours and preparing graphene oxide slurry materials at 25 degrees C for 2 hours. The graphene oxide slurry material is washed until neutral and dried to obtain oxidized graphene. The oxidized graphene is diluted with 8 mg/ml aqueous graphite oxide solution and polyethylene glycol monomethyl ether perfluorinated nonene, hydrated using hydrazine at 90 degrees C, stirred for 3 hours, washed after completing reaction and filtered to obtain modified graphene. The modified graphene is dispersed in distilled water and alkylene ultrasonically under a power of 180 W for 1.5 hours to obtain modified graphene water dispersing liquid. The modified graphene water dispersing liquid is heated with sulfur, lithium sulfide and water at 60 degrees C, mixed for 10 hours, allowed for adjusting pH to 2.5 by diluting with hydrochloric acid solution, mixed with sulfur composite material and carbon nanotube composites for 2.5 hours, washed with water and filtered to obtain a certain thickness of wet graphene composite paper. The wet graphene composite paper is pressed under a pressure of 30 MPa to obtain graphene composite film. The graphene composite film is placed in graphene composite film, filled with nitrogen gas at 3500 degrees C, 3000 degrees C and 2500 degrees C under gradient crystallization process to obtain the finished product.