The transmission characteristics of hollow metallic film-coated circular waveguide for THz radiation have been theoretically analyzed. We compared the theoretical attenuation coefficients of THz radiations with different incident frequencies in hollow circular waveguides with a bore diameter of 2mm with different metallic coating films of Au,Pb and Ni,and,for a given incident frequency,calculated the relationships between attenuation coefficients of the dominant mode TE11 and the bore diameters of hollow waveguides with different metallic coating films. Further investigations indicated that Au,Ag and Cu can all be used as excellent metallic coating films in hollow circular waveguides for the transmission of THz radiations with low attenuation coefficients.