In this work, the multicomponent nanocomposites containing filamentary carbon nanostructures were synthesized using materials based on iron oxides with a predominant content of the epsilon phase (epsilon-Fe2O3). These iron oxide-based materials were obtained by a direct plasma-dynamic synthesis with supersonic outflow of an iron-containing electric discharge plasma into an oxygen atmosphere. Subsequently, they were used as an initial precursor and placed in the plasma-chemical reactor, where the multicomponent C/SixOy/Fe2O3 nanostructures were synthesized under the influence of the pulsed electron beam. This method was based on the volume excitation of the reaction gas by a pulsed electron beam in such a way as to control the uniform process implementation in the entire excitation region. The morphology and phase composition of the synthesized C/SixOy/Fe2O3 nanocomposites were studied. A typical morphological feature of the C/SixOy/Fe2O3 samples was found to be the formation of filamentary nanostructures. Their diameter does not exceed 10-20 nm, while their length varies up to 1 mu m.