Abstract: A cross-shaped metamaterial absorber was desi gned. The S parameters and absorptivity were calculated by CST studio suite 2009, and the frequency domain solver was utilized. The absorber shows two absorption peaks of 0.83 at 24.65 THz and 0.997 at 35.25 THz. Through changes of the size of elements, a metamaterial perfect absorber with near-unity absorbance is achieved in 7.3 THz. To magnify 1 000 times of the absorber size in terahertz frequency, the perfect absorber can be achieved in the GHz frequency, thus providing a means to dynamically control the absorbing band. In addition, the absorbing mechanism was studied. Simulations reveal that the majority of energy is dissipated in the metallic cross plane. This type of metamateial absorber can be designed for the bolometer detector.