Abstract: Experiments concerning extracting polysaccharide from dehulled mung bean have been conducted.Particularly, the effects of factors ( extraction time, the ration of raw materials to water, extraction times and extraction temperature) on the yield of polysaccharide had been studied as well. Based on the single- factor experiments, response surface methodology had been employed to optimize extraction conditions. Results indicated that the optimum conditions for polysaccharide from dehulled mung bean extraction were: water temperature of 95.5℃, a ratio of water to raw materials of 21 ∶ 1 ( V/m) and an extraction time of 3h. Under this conditions, the yield of polysaccharide reached 4.32%. Following this, Sevag methodology had been used to remove the protein contained in polysaccharide as well.After deproteination, the content of polsaccharide reached50.35% while there was still approximately 31.26% of protein.