Transmission characteristics and mode structure of both metal hollow fiber and dielectric-coated metal hollow fiber for terahertz wave are studied. Theoretical evaluation shows that the TE11 mode is dominant in metal hollow fiber and has high coupling efficiency when a linearly polarized light source is launched. HE11 mode is mainly supported in dielectric-coated metal hollow fiber with an optimum thickness for the dielectric film. The transmission loss of the TE11 and HE11 mode is 8.4 dB/m and 2 dB/m respectively at the wavelength of 200 μm for the hollow fibers with 1 mm bore size. The effects of optical constants of metals and dielectric materials on attenuation coefficient are also discussed to optimize the transmission performance of dielectric-coated metal hollow fiber. Aluminum is the best choice among the commonly-used metals based on published optical constants. The optimum value for the refractive index of the dielectric film is 1.41. According to the primary measuring results, polyethylene is a proper choice as its refractive index is 1.51 and it brings low absorption in terahertz waves.