The research progress of graphitic carbon nitride (g-C₃N₄) in the field of photocatalytic hydrogen production is reviewed. In order to improve its photocatalytic activity, the material selection, synthesis techniques and application examples of modifying g-C₃N₄ nanosheets by introducing functional components such as transition metals, nonmetals and noble metals are discussed. The aim is to deeply analyze how these modification strategies improve the limitations of pure g-C₃N₄ in terms of visible light absorption efficiency and the compounding rate of photogenerated carriers, providing new insights for related research.