On the basis of computer simulation technology (CST) software,the polarization characteristics of two-dimensional metal grating arrays in 0.1-10 THz region are numerically analyzed. Different periodic metal copper grating arrays with 20 nm thickness deposited on 500 μm thick high-resistance silicon substrate are experimentally prepared by photo-lithography and thin-film technology. Then, the transmission and reflection characteristics of the structure are measured by Fourier transform spectrometer. Results show that the grating arrays have good polarization characteristics of the transmission and reflection in terahertz broad-band,and the polarization range can be adjusted by the structural period. Our results provide a reference for the further study and application of THz polarizer.