Polygonatum sibiricum polysaccharide (PSPs) possess multiple bioactivities， including antioxidant and hypoglycemic effects. It is rich in hydroxyl groups and the triple helix structure of Broussonetia papyrifera， which endows it with the ability to bind with gluten proteins and starch through hydrogen bonds， hydrophobic interactions， and other mechanisms， thereby effectively improving the processing quality of flour-based products. Studies have shown that the polysaccharides in Polygonatum sibiricum powder can regulate the digestion of Triticum aestivum starch through multi-level interactions， thereby endowing products with low glycemic index (GI) functionality. This review systematically summarized the structural features of PSPs and the influences of processing (e.g.， steaming) and extraction methods on them. It focused on three key mechanisms: Molecular interactions (e.g.， hydrogen bonding)， physical barrier formation， and the regulation of starch gelatinization and retrogradation kinetics， providing an in-depth explanation of how PSPs delay starch digestion， increased resistant starch content， and reduced the predicted GI. Furthermore， the application effects of Polygonatum sibiricum in low-GI staple foods such as noodles， rice cakes， and rice flour were summarized， along with an analysis of its improvements on dough rheology and texture， as well as the associated challenges. By comparing PSPs with other common plant polysaccharides， this review highlighted their dual advantages of improving processing properties and actively regulating blood sugar. Finally， addressing the current lack of in-depth studies on microscopic interaction mechanisms， future research directions were proposed， including the use of computational simulations and advanced characterization techniques to elucidate their structure-activity relationships. This study aimed to provide a theoretical foundation for the further development and high-value utilization of Polygonatum sibiricum in the field of functional cereal foods.