Food-derived polysaccharides are gaining popularity across diverse food applications due to their wide-ranging bioactivities and distinctive properties. The specific targeting of glycoside hydrolases towards glycosidic bonds lays the groundwork for synthesizing and exploring specific structural segments of polysaccharides, offering crucial implications in the food industry. However, macromolecular polysaccharides demonstrate limited biological activities as their active centers are tightly enveloped, posing challenges for traversing cell membrane barriers. By selectively cleaving partial glycosidic linkages in polysaccharides, glycoside hydrolases decrease the polymerization of polysaccharide molecules and effectively change the structural characteristics, where a series of smaller polysaccharide fragments can be generated for improving the bioactivities and properties in some respects. This review examines the role of glycoside hydrolases in degrading food-derived polysaccharides, the structure-function relationships, reaction conditions, and the current application status of degraded polysaccharides is discussed in particular. In addition, we also highlight challenges and future directions worth attention in the application of enzymes and polysaccharides. Overall, the present review will provide an efficient method for producing bioactivity-enhanced polysaccharides, which can improve the effectiveness and safety of functional foods to safeguard human wellness.