The tribological and mechanical properties of carbon nanofiber filled polytetrafluoroethylene/ polyimide composites were studied in this paper. The effect of filler contents (0.5, 1, 1.5, 2, 2.5, 3 and 5 wt%) on the tribological and mechanical properties was examined. Also, the influence of various loads (100 N, 150 N and 200 N) and velocities (0.69 m/s and 1.4 m/s) on the tribological performance was investigated. The results show that the best friction and wear performance would obtained under different loads and velocities, which reduced by 56.7% (150 N, 1.4 m/s) and 72.6% (200 N, 0.69 m/s), respectively. And also, optimal mechanical properties were obtained. In comparison with the mechanical properties of polytetrafluoroethylene/polyimide composites, the tensile strength, elongation-to-break and impact strength of 1 wt% carbon nanofiber filled polytetrafluoroethylene/polyimide composites increased by 5%, 50% and 75%, respectively. The transfer films, worn surfaces and impact fracture surfaces were studied by scanning electron microscopy. The micrographs show that a proper content of carbon nanofiber is helpful for forming a smooth and continuous transfer film, which is essential for achieving good anti-wear property. Meanwhile, mechanical properties have been improved due to the interfacial interaction between the matrix and carbon nanofibers.