▎ 摘　　要

NOVELTY - Preparing graphene quantum dot comprises dispersing graphene oxide in water by adding an amine passivator, reacting carboxy and hydroxy functional groups of graphene oxide during hydrothermal reaction, and passivating graphene oxide to obtain graphene quantum dot of high quantum yield. USE - The graphene quantum dot is useful for preparing composite material, photoelectric material and biosensor (claimed). ADVANTAGE - The method is environment-friendly, has simple preparation process, produces high yield of quantum dot, can easily regulate the nature of the product by changing the passivator, and is suitable for large scale preparation.