In this paper, a series of novel BaTiO 3 @MWCNTs core/shell heterostructure have been successfully synthesized via the solvent-thermal method. By adjusting the molar ratio of BaTiO 3 and MWCNTs, BaTiO 3 @MWCNTs heterostructure with different morphologies and electromagnetic absorb performances were obtained. Energy dispersive Spectrometer and X-ray diffraction analysis reveal that the product is composed of Ba, Ti, O and C elements and the crystal structure of BaTiO 3 is cubic perovskite. Besides, SEM and TEM images show that MWCNTs cores are coated with BaTiO 3 shells, which are self-assembled by BaTiO 3 nanoparticles. Moreover, the absorption peaks shift from high frequency to low frequency as the calculated absorber layer thickness increases. Most importantly, the maximum peak value of BaTiO 3 @MWCNTs heterostructure (10:1) reaches −45.0dB at 5.5GHz when the thickness of absorber layer is 3.5mm.