Abstract: Plant polysaccharides were an important component in plants. They had many biological activities and played an important role in human health. The biological activity of plant polysaccharides in vitro were related to its structure. The biological activity of plant polysaccharides in vivo were related not only to its structure but also to the process of digestion,fermentation and absorption. Many plant polysaccharides had biological activities when they were absorbed into the cells after digestion or fermentation. In this review,the key point was the classification,structural property,digestion,fermentation and absorption of plant polysaccharides,and the studies on its structure-activity relationship,digestive and fermentative characteristics were summarized in recent years. The results would provide a certain scientific guidance for the further in-depth research and development of plant polysaccharides.