Abstract: The insoluble dietary fiber (HIDF) was extracted from Polygonatum sibiricum residue by response surface methodology. Firstly, the effects of solid-liquid ratio, papain concentration, papain hydrolysis time, α-amylase concentration and α-amylase hydrolysis time on the extraction rate of HIDF were discussed by single factor experiments, the extraction process parameters were optimized by response surface methodology (Box-Behnken). Finally, infrared spectrum analysis, X-ray diffraction and scanning electron microscope observation were carried out, the functional properties were determined. The results showed that the optimum extraction conditions were as follows: Solid-liquid ratio 1:20 mL/g, papain concentration 0.13%, papain enzymolysis time 1.9 h, α-amylase concentration 0.29%, α-amylase hydrolysis time 2 h, the content of HIDF was 52.184%. The hydraulic holding capacity, oil holding capacity and swelling capacity of HIDF were 5.99±0.05 g/g, 3.965±0.04 g/g and 4.565±0.05 mL/g, respectively. Therefore, HIDF extracted from Polygonatum sibiricum residue had good physical and chemical properties and was suitable for processing into functional food, which provided a reference for improving the utilization rate of Polygonatum sibiricum residue and further excavating its nutritional value.