A three-dimensional fabric structure attained by three-dimensional fabricating and metalized fiber doping is researched. Its millimeter attenuation characteristics in 3 mm and 8 mm are tested and researched. And the characteristics are analyzed according to Mie scattering in electromagnetic wave and absorption theory. Experimental results show that echo signals in millimeter wave can be attenuated effectively by double actions of scattering and absorbing from the three-dimensional fabric structure. And the attenuation characteristics are in accordance with Mie scattering in electromagnetic wave and absorption theory.