The invention discloses 
oligosaccharide with 
insulin resistance activity intervention effects and a preparation method thereof, and the preparation method comprises the following steps: Chinese yam 
degreasing, deproteinization, 
pigment removal, purification, enzymolysis and 
dialysis and refining, wherein the enzymolysis step is as follows: purified Chinese yam 
polysaccharide powder is dissolved bydistilled water, the pH value is adjusted, undecanol and 
petroleum ether are added, then polygalacturonase, beta-galactosidase, beta-mannase and beta-
glucanase are sequentially added, ultrasonic-assisted enzymolysis, 
enzyme inactivation, cooling and 
centrifugation are carried out, and supernate is taken for later use. The preparation method disclosed by the invention has the beneficial effects that ultrasonic wave assistance is used, the polygalacturonase, beta-galactosidase, beta-mannase and beta-
glucanase are sequentially utilized to carry out step-by-step enzymolysis on the Chinese yam 
polysaccharide, hydrophobic substances undecanol and 
petroleum ether are added, by cooperation with the 
cavitation effect of the ultrasonic wave, a complex bonding structure of the Chinese yam 
polysaccharide is fully digested, the enzymolysis efficiency is greatly improved, and the method has the advantages of being convenient to operate, high in efficiency and free of 
pollution.