▎ 摘　　要

NOVELTY - A water-dispersible nitrogen doped graphene quantum dot is prepared by taking graphite oxide, reducing agent and nitrogen source, dispersing in water, ultrasonicating, performing hydrothermal reaction at 150-200 degrees C for 5-10 hours, freeze drying, adding concentrated sulfuric acid and oxidizing agent, carrying out oxidation reaction, adding super-pure water, separating and purifying, and freeze drying. USE - Method for preparing water-dispersible nitrogen doped graphene quantum dot (claimed). ADVANTAGE - The method is simple. The product has good water dispersibility, and is suitable for energy, sensing and medicine fields.