Metallic wire gratings in terahertz frequency were designed and fabricated by femtosecond micromaching and sputtering technique. The polarized transmission spectra of the gratings were characterized by terahertz (THz) time domain spectroscopy. The theoretical simulations based on FDTD method show a good agreement with experimental results. The physical origin of impacting transmittance in S and P polarization was analyzed. The results obtained from this work provide a useful referrence for the production of THz polarization devices.