The invention relates to the field of polysaccharide compound, in particular to a polysaccharide prebiotic, and a preparation method and an application of the polysaccharide prebiotic. The polysaccharide prebiotic comprises the following raw materials in percentage by weight: 10-15% of mannose, 1-5% of rhamnose, 35-60% of glucose, 25-40% of galactose and 1-5% of xylose. The polysaccharide prebiotic is prepared by degreasing, refrigeration, wall breaking, enzymolysis, water extraction and purification sequentially. The polysaccharide prebiotic overcomes the defects that the prebiotic in the prior art contains a relatively single formula component and does not have an obvious intestinal flora regulation effect; the polysaccharide prebiotic has the advantages that the polysaccharide prebioticcan effectively regulate the quantities of profitable florae and harmful florae and improve balance of the florae in an intestinal tract of a human body; at the same time, an extraction method is simple; and the extraction efficiency is high.