Abstract: Polysaccharide nano-selenium (polysaccharide selenium nanoparticles, Polysaccharide-SeNPs) exhibits unique properties and biological functions, offering limitless potential and promising applications in various fiels such as medicine, food and pharmacology. This review mainly focuses on the structure and properties of polysaccharides, nano-selenium (selenium nanoparticles, SeNPs) and the complementary combination of polysaccharides and SeNPs. SeNPs utilizes the hydrogen or Se-O bonds on its surface, thereby achieving dispersion and stability. The article provides a summary of the preparation conditions, methods, and optimization strategies for Polysaccharide-SeNPs. Currently, chemical synthesis methods are commonly used to produce Polysaccharide-SeNPs, with auxiliary techniques such as ultrasound, vacuum, high pressure, or enzymes employed to enhance yield or biological activity. Furthermore, the article reviews representative biological effects of Polysaccharide-SeNPs reported in the international literature over the past five years. Finally, emphasis is placed on the application and progress of Polysaccharide-SeNPs in the fields of medicine, food, pharmaceuticals, and health products. The study of Polysaccharide-SeNPs expands new perspectives in the field of traditional Chinese medicine, particularly polysaccharides derived from Chinese herbal medicine, providing a valuable reference for exploring novel and highly biologically active "selenium-shaped" entities.