The application of near infrared spectroscopy (NIRS) in plastic sorting aims to identify plastic types and components, improve recycling efficiency, reduce environmental impact, and finally realize comprehensive utilization of resources. This paper firstly introduces the traditional sorting technology of plastics. Secondly, the principle of near infrared detection technology and its application in the field of plastics are summarized. Finally, the application prospect in the field of plastic separation is summarized and prospected. In the field of plastic sorting, compared with the traditional physical and chemical detection methods, near infrared spectroscopy detection technology has obvious advantages such as fast, non-destructive and efficient, and can identify and sort the tested object through real-time and online detection, qualitative and quantitative ways. Although the technology has achieved remarkable stage results in some experimental studies, it still needs further research and optimization in practical engineering applications, especially in the accuracy of detection and new application scenarios.