Graphitic carbon nitride (g-C₃N₄), as a fascinating two-dimension material, has attracted dramatic interest due to its unique properties and inexpensive synthesis precursors. In this work, we treated g-C₃N₄ from the perspective of its planar structure and copper oxide (CuO)/g-C₃N₄ hybrids were prepared via an in-situ growth process. The tribological properties of the hybrids were evaluated by adding them into polyimide (PI) composites. Variations in the contents of the hybrids and different applied loads, sliding speeds were used to systematically investigate the tribological performance of PI composites. Comprehensive analysis on the wear tracks, fractured surfaces and tribofilms were conducted to reveal the synergetic effect between CuO and g-C₃N₄ nanoparticles. The overall results indicated that CuO/g-C₃N₄ hybrids were potential anti-wear additives for polymer-based materials.