Abstract: Heterojunction photocatalytic materials show excellent ability in degrading toxic and harmful pollutants. In this study, we prepared TiO₂-g-C₃N₄ and TiO₂-g-C₃N₄-Bi₂O₃ heterostructure photocatalytic materials by ball milling. The photocatalytic performance of TiO₂-g-C₃N₄ and TiO₂-g-C₃N₄-Bi₂O₃ towards phenol organic wastewater were investigated under different light source, as well as the effects of light source on the degradation performance. Under the single visible light or ultraviolet light, the ternary TiO₂-g-C₃N₄-Bi₂O₃ shows higher photocatalytic activity than TiO₂-g-C₃N₄. And under visible light conditions, the degradation performance of TiO₂-g-C₃N₄-Bi₂O₃ is much better than TiO₂-g-C₃N₄. Under the simultaneous irradiation of visible light and ultraviolet light, the degradation efficiency of TiO₂-g-C₃N₄-Bi₂O₃ and TiO₂-g-C₃N₄ on phenol wastewater reached 99.44% and 96.67%, respectively. The characterization results show that the doping of Bi₂O₃ remarkably enhances the absorption of light by the catalyst in the full spectrum, and the construction of the ternary system promotes the separation of photogenerated electrons and holes. The research results show that the ternary TiO₂-g-C₃N₄-Bi₂O₃ can be achieved through a feasible ball method of milling-microwave heating-calcination process, and confirms the promising prospects of TiO₂-g-C₃N₄-Bi₂O₃ in organic wastewater treatment.