Two kinds of terahertz polymer waveguides were designed,and the outer wall of one is coated by gold film with ring groove and the inner wall of the other is coated by copper film with spiral groove. Attenuation and dispersion characteristics of two kinds of waveguides were analyzed and compared. In the terahertz band,terahertz wave attenuation of the gold coated waveguide is larger than that of the other; and the dispersion of the gold coated waveguide is smaller than that of the other,and there exists negative dispersion phenomenon. Research results show that the inner copper coated waveguide is suitable for terahertz transmission,while the outer gold coated waveguide is not suitable for terahertz transmission because it has larger terahertz loss. Through analyzing electrical and magnetical characteristics of the two,there is not surface plasmon phenomenon.