This study aimed to promote the separation of photogenerated carriers and improve the redox performance of graphite carbon nitride (g-C₃N₄) by synthesizing a double-heterojunction-structure photocatalyst, g-C₃N₄/(101)-(001)-TiO₂, through the solvothermal method. The photocatalyst comprised a Z-system formed from g-C₃N₄ and the (101) plane of TiO₂, as well as a surface heterojunction formed from the (101) and (001) planes of TiO₂. The results showed that g-C₃N₄/(101)-(001)-TiO₂ had strong photocatalytic activity and stable performance in the photodegradation of paracetamol. The active species ·O₂⁻ and ·OH were found to play important roles in the photocatalytic degradation of paracetamol through a radical-quenching experiment. The charge-transfer mechanism was also described in detail. Overall, this work provided a new strategy for the Z-system heterojunction and opened up the application of this structure in the degradation of organic pollutants.