Abstract: OBJECTIVE To study the isolation and composition of polysaccharides from Trichosanthis Radix. To determine and compare the content of polysaccharides in different harvest time. METHODS The monosaccharide composition was determined by GC and TLC. The content of polysaccharides was measured by modified phenol-sulfuric acid method. RESULTS The results indicated the polysaccharide was composed of glucose. The contents of polysaccharide were 7.51%, 6.16%, 10.40%, 18.90% and 17.81% respectively in five samples of Trichosanthis Radix. CONCLUSION The monosaccharide composition in polysaccharide from Trichosanthis Radix is glucose. The content of polysaccharides in Trichosanthis Radix of different harvest time is obviously different. The highest levels of polysaccharides among the samples are in December and January respectively. The results are useful to determinating the best harvest time of Trichosanthis Radix.