▎ 摘　　要

NOVELTY - Preparing graphene quantum dot comprises (1) taking carbon black disposed in mixed acid, stirring mixture under reflux to obtain mixed solution; where the mixed acid is mixture of concentrated sulfuric acid and concentrated nitric acid; and (2) cooling the mixed solution in the step (1) to room temperature, adjusting pH of mixed solution to neutral, and acidifying to pH = 1-2 to obtain graphene quantum dot. USE - The method is useful for preparing graphene quantum dot. ADVANTAGE - The graphene quantum dot: has uniform and stable particle size, and edge carboxy groups can be stably present in product for long time. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for the graphene quantum dot is prepared by above mentioned method.