Abstract: The waveguide-type artificial structure can be used to realize the terahertz biosensor, which is a kind of important terahertz device.Terahertz waveguide is one of the great significance in terahertz technology and applications.The transmission characteristics of terahertz wave in rectangular hollow metal waveguide are analyzed by using the electromagnetic simulation software CST, and the S21 parameters of hollow metal waveguide with groove and dielectric loading are compared with different incident frequencies.The terahertz spectroscopy experimental results are also compared, analyzed and verified.