Poly(phenol-formaldehyde resin)/carbon fiber composites with different ratios of graphene–Fe₃O₄ were manufactured through a molding press process. Fe₃O₄ was introduced into the graphene to avoid recombination of the layers. The effects of the amount of added graphene–Fe₃O₄ on the morphology, thermal conductivity, friction performance and thermal properties of the composites were investigated via scanning electron microscopy, thermal constants analysis, tribology and thermogravimetric tests. Scanning electron microscopy confirmed the enhanced friction surface of the composites and the combination of the resin with the fibers. The thermal conductivity measurements showed that the best results were achieved with 2.0 wt% graphene–Fe₃O_4. The friction coefficient and wear rate also decreased with the addition of graphene–Fe₃O₄ based on the tribological results.