▎ 摘　　要

NOVELTY - Preparing nanocomposite fluorescent hydrogel based on graphene quantum dot, comprises adding mixed reactants and initiators to the graphene quantum dot solution, uniformly stirring to obtain a mixed solution, placing at -20 to -50°C for 5-72 hours, soaking in deionized water, taking out after 24 hours to get a nanocomposite fluorescent hydrogel based on graphene quantum dots, the mixed reactant is mixed reactant I, the aqueous solution of hydrophilic polymer or mixed reactant II, the mixed reactant I is a monomer and a catalyst, and the mixed reactant II is a monomer and an aqueous solution of a hydrophilic polymer, the monomers are acrylic acid, acrylamide, N-methylolacrylamide, N,N-dimethylacrylamide or methacrylic acid, the hydrophilic polymer is polyvinyl alcohol or polyethylene glycol. The particle size of the graphene quantum dots in the graphene quantum dot solution is 2-20 nm. USE - The hydrogel is useful in fluorescence detection of metal ions in water (claimed). ADVANTAGE - The method is simple, the production cost is low, and is suitable for enlarged production.