Cross metal array structure is experimentally studied by terahertz time-domain spectroscopy (THz-TDS). The results show that this kind of structure have the characteristic of non-polarized narrow band filtering. Most terahertz wave can pass through the cross metal array structure. However, the terahertz wave with certain frequencies is restrained by the structure. Moreover, the change of polarization angle does not affect the position of transmission dip. It is proved that the structure is a good non-polarized transmission and filtering device in the terahertz band. These results provide a good reference for the research and fabrication of terahertz sub-wavelength optical components.