▎ 摘　　要

NOVELTY - Preparation of graphene comprises adding natural graphite powder into acidic aqueous solution dissolved with chitosan, ultrasonically dispersing, standing, low-speed centrifuging of upper layer, collecting liquid, high-speed centrifuging, removing supernatant, washing lower layer with deionized water, high-speed centrifuging repeatedly and vacuum-drying. USE - Method for preparing graphene (claimed) used in field of biomedicine. ADVANTAGE - The non-toxic graphene has structure which is free from oxidation defects. The method is simple, environment-friendly and has low cost.