In this paper, a crude polysaccharide (PDI) was extracted from D. indusiata volva. The antioxidant activities of PDI were examined by 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical, hydroxyl radical and ABTS radicals scavenge assay. The results showed that PDI had antioxidant activities in all these assays, indicating that it could be used as an antioxidant. Then a rapid and highly efficient micellar electrokinetic capillary chromatography (MECC) method coupled with diode array detector was developed to determine the monosaccharides composition of the polysaccharide sample. The optimum conditions were as follows: 20 mM borate (pH = 9.3) and 15 mM SDS as the electrophoresis medium, the separation temperature was 20 °C. Under these conditions, monosaccharides could be separated within 8 min. The polysaccharide of the volva was mainly composed of glucose, mannose, galactose and arabinose.