In order to explore the digestive characteristics of soy hull polysaccharide in gastrointestinal tract， the results show that: the total sugar and uronic acid content of soy hull polysaccharide did not change significantly from oral to small intestine during simulated digestion， its content fluctuated between 126 mg and 29 mg， however， the total sugar content began to decrease at 12 h of fermentation in the large intestine stage and significantly decreased to (71.02 ± 0.45) mg after 48 h of fermentation， the content of reducing sugar increased from (18.04 ± 0.15) mg to (81.13 ± 0.36) mg after digestion， and finally decreased to (51.55 ± 1.31) mg in the subsequent fermentation stage； the absolute value of the potential increased from 3.46 mV to 20.10 mV in the digestion stage and decreased significantly in the large intestine stage. After 48 h of fermentation， the absolute value of the potential changed to 15.26 mV； the particle size showed an obvious downward trend during the whole digestion stage， and the pH value did not change significantly during the oral to small intestinal stages， and decreased from 7.92 to 5.93 in the large intestine stage； the viscosity of digestive juice showed a decreasing trend.