Abstract: W-hexaferrites of Fe-poor formula BaZn_xCo_2-xFe_15.5O₂7 were prepared using solid state sintering method.The electromagnetic properties of ferrite composite were deeply studied by changing the substitution of Zn and Co contents.The experimental results indicate that the composites with the Fe-poor ferrite possess lower complex permittivity.Meanwhile, the resonance frequency and the complex permittivity of the ferrite composites can be controlled by regulating the content of substitution Zn and Co contents.Additionally, a few nano carbon-tubes were added to the composites to tailor the dielectric performance, which proves that the additions of carbon-tube in a certain range can excellently improve the microwave absorption properties of ferrite composites.