[C/Fe3O4]@C coaxial nanocables with electricity-magnetism-adsorption trifunctionality have been successfully synthesized by carbonization of the electrospun [polyacrylonitrile (PAN)/ferric acetylacetonate (Fe(acac)(3))]@polyacrylonitrile (PAN) coaxial nanocables. SEM and TEM observations reveal that the products are coaxial nanocables in morphology. The core diameter is ca. 125 nm and the shell thickness is ca. 82 nm. Electrical and magnetic properties analyses show that the [C/Fe3O4]@C coaxial nanocables possess tunable electrical conductivity and magnetic performance. The N-2 adsorption-desorption measurements demonstrate the specific surface area and the pore size of the [C/Fe3O4]@C coaxial nanocables are 322.6 m(2)/g and 33.6 nm, respectively. [C/Fe3O4]@C coaxial nanocables exhibit efficient adsorption for Rhodamine B and Cu2+ ions aqueous solution with excellent magnetic separation performance. The isotherms and kinetics of adsorption process are determined and analyzed in detail. The excellent adsorption capacity can be attributed to the porous structures, which will make them to be promising adsorbents for water treatment. This work provides a new insight into the design and development of functional carbon-based nanomaterials.