Leymus chinensis(Trin.) Tzvel.,widely distributed at eastern Eurasian steppe and divided into gray-green type and yellow-green type,has different stress resistance to environment.In the present study,the water-soluble polysaccharides from two ecotypes ofL.chinensis were analyzed in detail,and the differences between polysaccharides from the two ecotypes ofL.chinensis in the yield,monosaccharide composition,molecular weight and structure were clarified.The polysaccharides of L.chinensis were composed of both neutral and acidic polysaccharides.The neutral polysaccharides contained mannose,glucose,galactose,xylose and arabinose,and mainly consisted of β-1,4-Glcp,α-1,3-Galp and α-1,2-Xylp residues.The acidic polysaccharides contained mannose,rhamnose,glucuronic acid,galacturonic acid,glucose,galactose,xylose and arabinose.However,the yields,monosaccharides contents and the molecular weights of the polysaccharides from the two ecotypes of L.chinensis were different.Moreover,the resistance type(gray-green type) of L.chinensis contained a number of α-1,3-Manp and reducing end of β-Glcp residues,and much more O-methyl groups than normal type(yellow-green type) of L.chinensis.The differences of the polysaccharides of the two ecotypes ofL.chinensis might be due to the long-term environmental adaptability of plant,and the differences of the polysaccharides might influence the stress resistance of L.chinensis.