The panax genus is a widely used medicinal plant with good biological activity. As one of the main active components of the Panax genus, polysaccharides have various pharmacological effects. This review summarizes the latest research reports on ginseng, American ginseng, and Panax notoginseng polysaccharides and compares the differences in extraction, isolation and purification, structural characteristics, and biological activities. The current research mainly focuses on ginseng polysaccharides, and the process of extraction, isolation, and structure analysis of each polysaccharide is roughly the same. Modern pharmacological studies have shown that these polysaccharides have antioxidants, antitumor, immunomodulatory, antidiabetic, intestinal protection, skin repair, and other biological activities. This review provides new insights into the differences between the three kinds of ginseng polysaccharides which will help to further study the medicinal value of ginseng in traditional Chinese medicine.