The detection of crop quality is essential for ensuring the safety of crop circulation and storage. This involves the use of biochemical and optical detection technologies, with optical detection being preferred due to its high efficiency, non-destructive nature, and rapid characteristics. Terahertz wave technology offers favorable conditions for crop quality detection due to its unique properties, including transient, transmission, coherence, and low-energy attributes. In recent years, terahertz technology has demonstrated significant potential in crop quality detection. This paper provides a summary of the terahertz detection system, detection principle, and advantages, along with an in-depth analysis of the recent progress in the application of terahertz technology in crop quality detection. This includes disease detection, variety origin identification, transgenic identification, and other detection methods. Furthermore, the paper identifies and discusses the existing problems in the research and application of terahertz technology in crop quality detection, while also presenting potential development directions.