▎ 摘　　要

NOVELTY - Preparation of graphene comprises heating and carbonizing biomass. The heating carbonization adopts gradient heating. The gradient heating comprises seven-grade gradient. The highest temperature in the gradient heating process is not greater than 1600 degrees C. USE - The method is used for preparation of graphene. ADVANTAGE - The method improves micro-level integrity of graphene obtained from biomass without agglomeration.