NOVELTY - Preparing a graphene/silver nanocomposite material, comprises adding e.g. concentrated sulfuric acid and sodium nitrate in an ice-water bath to obtain graphene oxide and then adding potassium permanganate, heating mixture and then adding e.g. hydrogen peroxide to obtain a bright yellow product, vacuum freezing and drying the product, mixing aqueous graphene oxide solution and silver nitrate, heating the mixture and then adding sodium citrate, adding aqueous ammonia and hydrazine hydrate in the resulting solution to obtain a product, vacuum freezing and drying the product to obtain material.    USE - The method is useful for preparing a graphene or silver nanocomposite material (claimed), which is useful for a transistor, a photovoltaic device, a fuel cell and a super capacitor.    ADVANTAGE - The method enables efficient, simple and economic preparation of the graphene or silver nanocomposite material with high conductivity and density, large specific surface area and improved mechanical strength.    DETAILED DESCRIPTION - Preparing a graphene or silver nanocomposite material, comprises adding graphite, concentrated sulfuric acid and sodium nitrate in an ice-water bath to obtain graphene oxide and then adding potassium permanganate with stirring, heating the mixture at a temperature of 35|\5 degrees C for 30-60 minutes and then adding deionized water, further heating the mixture at a temperature of 95|\5 degrees C for 15-60 minutes and then adding hydrogen peroxide, continuously stirring the mixture until obtaining a bright yellow product, washing the product with hydrochloric acid, ethanol and deionized water, vacuum freezing the product and then drying, dissolving the graphene oxide in deionized water and then subjecting to ultrasonic treatment, mixing aqueous graphene oxide solution and silver nitrate, heating the mixture at a temperature of 90|\10 degrees C and then adding sodium citrate and stirring, adding aqueous ammonia and hydrazine hydrate in the resulting solution and then stirring at a temperature of 90|\10 degrees C to obtain a product, washing the product with ethanol and deionized water and vacuum freezing the product and then drying to obtain graphene or silver nanocomposite material.