Abstract: With the increase in frequency of vacuum electronic devices, the size of slow wave structure is reduced to tens of microns, and requirements for dimensional accuracy and surface roughness are constantly increasing during processing. The processing method of slow wave structure at terahertz frequency is introduced in this paper. The characteristics and research status of deep reactive ion etching (DRIE) and ultraviolet-Lithographie Galvanoformung Abformung (UV-LIGA) are discussed. The research progress of the folded waveguide with UVLIGA in national key laboratory of science and technology on vacuum electronics is also introduced.