Terahertz (THz) waves, also called T-rays, usually refer to electromagnetic waves with a frequency range of 0.1 to 10 THz. In recent years, with the improvement of terahertz instruments, terahertz systems have become easier to get applied, which have greatly promoted the research of many potential applications. Owing to its good detection ability and non-ionizing characteristics, it has important application value in studying the structural properties and dynamics of biomolecules, as well as in imaging of medical biological tissues. This article mainly introduces the characteristics of the terahertz technology and its application in the medical field, and finally forecasts the development trend of the terahertz technology in the medical field.