Abstract: The optimal craft process of extracting polysaccharides from pleurotus eryngii by hot water was studied in this paper.The preliminarily purified polysaccharides were obtained with the step of being leached by hot water,precipitated by ethanol and eliminated protein with Sevag method.The content of polysaccharides was determined by colourimetry using sulfuric acid and phenylic acid.Then the optimal conditions were obtained by orthogonal test on the basis of single factor test.The results indicate that the optimal conditions by orthogonal test are as following:time 3 hour,the temperature of water 90℃,the volume of ethanol is 70% compared to the volume of extracting solvent and the ratio of water to material is 1:20.At this time,the maximal yield of polysaccharides is 2.88%.

Key words: polysaccharides of pleurotus eryngii, extraction craft, yield of polysaccharides