<p>Graphitic carbon nitride (g-C₃N₄) is a typical non-metallic n-type semiconductor. Due to its good chemical stability, low cost, no secondary pollution, and ability to respond to visible light, the g-C₃N₄ material has important application prospects in the field of photocatalysis. This study constructed a complex system of photocatalysis and advanced oxidation processes by combining g-C₃N₄ with hydrogen peroxide (H₂O₂) for efficient photocatalytic degradation of organic pollutants. Firstly, using urea as raw material, the g-C₃N₄ photocatalytic products were prepared via thermal polymerization reaction, and the effect of calcination temperature on the properties of g-C₃N₄ materials was studied. Subsequently, the photocatalytic degradation performances of the g-C₃N₄ photocatalytic system on organic pollutants with and without the H₂O₂ addition were investigated by using methylene blue (MB) and rhodamine B (RhB) as the target pollutants. The research results indicate that the g-C₃N₄ product obtained at 580 ℃ exhibited excellent degradation ability towards organic dyes. With the addition of H₂O₂, the degradation rates of MB and RhB can reach about 94.2% and 95.3% within 50&#xa0;min, respectively. Finally, the degradation mechanism of organic pollutants by the complex system in photocatalytic reactions was explored. This work provides some significant insights into the synergistic effect between photocatalysis and advanced oxidation processes by combining simple unmodified g-C₃N₄ with H₂O₂ in the degradation of organic dye pollutants.</p>