Novel cage-like and electromagnetic functional polyaniline (PANI)/CoFe2O4 composite nanostructures, in which the self-assembled PANT nanofibers (similar to 15 nm in diameter) entwined around the octahedral CoFe2O4 magnet acting as the nucleation site or template, were successfully prepared by FeCl3 as either oxidant and dopant via a self-assembly process. The coordination effect of the magnet as a nucleation site or template and the magnetic interaction between the PANI nanofibers and CoFe2O4 as a driving force results in such cage-like nanostructures. The cage-like composite nanostructures not only have high conductivity (sigma(max) similar to 5.2 S/cm), but also show a typical ferromagnetic behavior.