To design the optimal protection scheme for cultural relics of different materials and production techniques, the cultural heritage scientists are in constant search of the most effective nondestructive testing method for the overall survey of the cultural relics. Due to the unique properties of terahertz wave's low energy, strong penetrability for non-metallic and nonpolar substances, simultaneous measurement of amplitude and phase information, strong anti-interference capacity, etc., terahertz technology has been gaining an edge over other conventional nondestructive testing methods. In this review paper, the latest progress of terahertz technology applied in nondestructive testing of cultural relics are introduced, and the terahertz spectra characteristics of various cultural relics materials are illustrated. The principle and characteristics of terahertz imaging detection technology are expounded. The key issues in the application of terahertz nondestructive testing technology for various cultural relics are discussed, and the most successful and representative application examples of terahertz technology in cultural relics science are listed. Finally, we present the developing trend of terahertz nondestructive testing technology in the field of cultural relics.