Abstract: The low energy, broadband and unique time-domain pulse properties of terahertz wave, make it of important value in the area of material and matter science, etc. A home-made terahertz time-domain spectroscope (THz TDS) based on the photoconductive antenna (PCA) technique was built. The principle of terahertz wave emission and detection based on the PCA technique was firstly introduced, and the optical path designing, setting up and testing, function expanding, and application example analyzing were also elucidated in detail. The study provides a method and experience for the researchers who need to build a home-made high performance THz TDS.