Simulation analysis of transmission of light in sub wavelength metal holes array diverse from 300 900 nm has been done through building a three dimensional model and finite difference time domain method（FDTD）. The transmission is heavily influenced by variant characteristic parameters, such as radius, period, thickness and packing medium. At last some curves of wavelength and transmittance have been derived through FDTD solution software when parameters change. The results show that the transmittance become higher when radius is large, but the tendency is adverse to the period. The transmittance turns out to be the highest when the medium in front of the metal match the back, which lay the foundation for designing an optical filter.