Terahertz (THz) wave is electromagnetic wave in the frequency range of 0.1?10 THz, which has the characteristics of low energy, broadband, fingerprint spectrum, and sensitivity for water. With the development of THz technology, THz imaging technology has shown many unique advantages in the fields of biomedical diagnosis, nondestructive testing, and security inspection, and has gained more and more widespread attention. This paper mainly overviews the common THz imaging techniques. The imaging principles and research progresses of pulsed THz imaging technology, continuous THz imaging technology, THz near-field imaging technology, and THz real-time imaging technology are introduced in detail, respectively. The typical applications of THz imaging technology in the fields of security inspection, nondestructive testing, and biomedicine are also introduced. Furthermore, the future development of THz imaging technology is prospected.