Optoelectronic terahertz generation and detection play a key role in the applications of non-destructive testing, which involves different areas such as physics, biological, material science, imaging, explosions detection, astronomy applications, semiconductor technology and superconductiong electronics. In this article, we present a review of the principle and performance of typical terahertz sources, detectors and non-destructive testing applications. On this basis, the new development and trends of terahertz radiation detectors are also discussed.