Polysacaccharide extract isolated from Mycoleptodonoides aitchisonii was examined for its chemical properties and immuno-modulating activity.To investigate the immunomodulating activity on extraction conditions, Mycoleptodonoides aitchisonii was extracted using water (reflux at 50, 60, 70, 80, 90 and 100 ℃).When water extracts were further fractionated into crude polysaccharide, yields of polysaccharide samples were decreased at increased temperature.