Abstract: Three-dimensional Fe₃O₄ decorated carbon nanotubes/reduced graphene oxide foam/epoxy (3D Fe₃O₄-CNTs/rGF/EP) nanocomposites with highly oriented three-dimensional structures were fabricated by facile template method. Scanning electron microscope (SEM), transmission electron microscope (TEM), thermal gravimetric analyses (TGA), X-ray photoelectron spectroscopy (XPS) and Raman all proved the successfully graft of Fe3O4 onto the surface of CNTs and the formation of interconnected 3D highly aligned porous framework inner Fe₃O₄-CNTs/rGF. Owing to the presence of Fe₃O₄ and 3D nanohybrid framework, the obtained 3D Fe₃O₄-CNTs/rGF/EP nanocomposites with 0.24 wt% rGF and 2.76 wt% Fe₃O₄-CNTs showed remarkable electrical conductivity of 15.3 S/m and wonderful EMI SE value of 36 dB within the X-band range, almost 482% enhancement compared to physically blended Fe₃O₄-CNTs/EP nanocomposites without three-dimensional structure (～6 dB). The excellent magnetic property and efficient 3D framework structures are considered as the main reasons for outstanding EMI shielding performances of the 3D Fe₃O₄-CNTs/rGF/EP nanocomposites.