Plant polysaccharides are polymers derived from plants with complex structures and various biological activities. Polysaccharides have a beneficial effect on hosts by regulating their intestinal flora, which has become a hot research topic in recent years. Studies have shown that the intestinal flora can metabolize non-starch polysaccharides into short-chain fatty acids, exerting a variety of physiological functions such as regulating host metabolism, immune system and cell proliferation, improving the intestinal environment, and ultimately promoting human health. The chemical structure and physical properties of plant polysaccharides are the basis for their differential utilization by the intestinal flora and determine the strength of their prebiotic effects. The structure of plant polysaccharides varies depending on the extraction, purification and modification methods used, affecting their activity. This paper systematically discusses the prebiotic effects of plant polysaccharides and the factors that affect their structure, which will provide a reference for the precise development and utilization of plant polysaccharides.