Abstract: Graphite carbon nitride (g-C₃N₄) has great application potential in the new energy development and environmental remediation, but the shortcomings of pure g-C₃N₄, such as small light absorption range, high crystallinity, high photo-generated carrier recombination rate and few active sites, limit its application range. The introduction of carbon dots (CQDs) to construct composite phase can increase the reactive sites of g-C₃N₄, accelerate the transfer of surface charges, inhibit the recombination of carriers, and then enhance its photocatalytic activity. The preparation methods and raw material sources of CQDs, the synthesis methods (solvothermal method, calcination method and self-assembly method) of CQDs/g-C₃N₄ composites and the strategies for improving photocatalytic performance were reviewed. The applications of CQDs/g-C₃N₄ composites in hydrogen production, pollutant degradation and antibacterial in recent years are described. Finally, the future development direction of CQDs/g-C₃N₄ composites is prospected.