Abstract: Banana skin polysaccharide which has obvious anticancer activity was extracted from banana skin as raw material.The optimum extracting conditions were investigated through single factor experiments combined with orthogonal test.And molecular weight distribution of banana skin polysaccharide was measured by using gel permeation chromatography(GPC).The results show that the optimum extracting conditions are:ratio of banana skin to water 1:20,and temperature 70℃ for 4 times.1.5h each time.The yield of banana skin polysaccharide is 4.25% under the optimum conditions.It is shown by GPC analysis that the number average molecular weight and the weight average molecular weight of banana skin polysaccharide obtained are 427540 and 433160 respectively.And the distribution width of molecular weight is 1.031,which indicates that the molecular weight distribution of polysaccharide in banana skin is concentrated and narrowly distributed.

Key words:  , banana skin； polysaccharide； extracting condition； molecular weight distribution；