Objective Compare the content and composition of polysaccharide in fibrous root and tuber of Bletilla striata（Thunb. ） Reichb. f. . Methods Extract the polysaccharide of the fibrous root and tuber of Bletilla striata with water extraction and ethanol precipitation； Phenol-sulfuric acid method and 3， 5-dinitrosalicylic acid（DNS） method were carried out to evaluate the polysaccharide of the pseudobulb part of Bletilla striata； using GC-MS analysis of fibrous root and tuber of monosaccharide composition of polysaccharides. Results The fibrous root polysaccharide content is lower than the polysaccharide content in the tubers； The reducing sugar content is higher than the tuber； The fibrous root and tuber of polysaccharide containing glucose and mannose， but also contain galactose in fibrous root. Conclusion The fibrous root and tuber of Bletilla striata in the content of total sugar， reducing sugar， monosaccharide composition are plants. This is regrettable because phytoalexins or different， polysaccharide content of tubers is more than fibrous， but has certain potential medicinal value， is worth further development.