Abstract: The thickness, carbon fiber felt (CFF) content, and the carbon (CB) filling of CFF/epoxy (EP) multilayer composites are designed. With the design result, several kinds of multilayer composites are prepared, and their shielding effectiveness is studied. It is found out that the shielding performance enhances with the increasing of thickness, and that the shielding effectiveness of the multilayer composite increases with the increasing of the CFF content, and that the addition of CB can enhances the shielding effectiveness further. The location of CB in multilayer composite has a great influence on the shielding effectiveness. The shielding effectiveness of the CFF & CB-GFF is about 71 dB at 4.00 GHz, and the CFF & CB-GFF can be a good shielding material with excellent structures and functions.