The dietary fiber in mung bean skin was used as an experimental object in this experiment. In order to improve functional properties of dietary fiber in mung bean skin， we examined the effect of extrusion and/or enzymatic hydrolysis treatment on water holding capacity， oil holding capacity， swelling capacity， cation exchange capacity， glucose adsorption capacity and cholesterol adsorption capacity of skin dietary fiber in mung bean. We also investigated the effect on structural properties of dietary fiber in mung bean skin by scanning electron microscope， X-ray diffraction and Fourier transform infrared spectroscopy. The results showed that the combined treatment could more significantly modify the properties of dietary fiber in mung bean skin than either treatment alone. Compared with the dietary fiber in mung bean skin before and after modification， the water holding capacity， oil holding capacity， swelling capacity， cation exchange capacity and glucose adsorption capacity were enhanced by 1.46， 1.15， 1.87， 6.98 and 1.66 times in the combined treatment group， respectively. The cholesterol adsorption capacity was (2.38±0.05) mg/(mL·g) at pH 2， and (3.45±0.12) mg/(mL·g) at pH 7. The results of scanning electron microscope analysis indicated that the surface structure of dietary fiber in mung bean skin after combined treatment was loose， and more wrinkles and porous characteristics appeared. X-ray diffraction and Fourier transform infrared spectroscopy analysis indicated that the relative crystallinity of dietary fiber in mung bean skin after combined treatment was the lowest， and some cellulose components were redistributed to transform into soluble dietary fiber (SDF). Therefore， extrusion combined with enzymatic hydrolysis treatment can be used as a better method to modify dietary fiber， providing theoretical basis for improving the utilization rate of dietary fiber in mung bean skin and further exploiting its nutritional value.