The invention relates to the field of 
lentinus edodes, and provides a method for rapidly extracting 
polysaccharide from 
lentinus edodes. The method is characterized in that 
lentinus edodes or stems thereof are subjected to crushing, soaking, flash extracting, extract liquid centrifuging, deproteinizing, micro-filtrating, 
reverse osmosis, and 
microwave vacuum drying, such that lentinus edodes 
polysaccharide is obtained. The method comprises the specific steps that: 
raw material selection and pretreatment are carried out, wherein dried lentinus edodes or stems thereof are crushed and soaked; flash extracting is carried out, wherein the lentinus edodes soaking liquid is extracted by using a flash extractor; 
centrifugation is carried out, wherein the extract liquid is centrifuged, such that a supernatant is obtained; deproteinizing is carried out, wherein 
neutral protease is added into the supernatant, and 
enzyme-method deproteinizing is carried out; micro-filtrating is carried out, wherein 
suspended solids such as crude 
fiber and 
pectin are removed from the deproteinized liquid by using a 0.2-0.5mum 
microfiltration membrane; 
reverse osmosis concentration is carried out, wherein the micro-filtrated liquid is subjected to 
reverse osmosis concentration; and 
microwave vacuum drying is carried out, wherein the 
polysaccharide concentrated liquid is subjected to 
microwave vacuum drying, such that the lentinus edodes polysaccharide is obtained. The technical scheme provided by the invention has reasonable 
process configuration, such that 
operation time is effectively shortened, and operation efficiency is improved. Process linkage 
automation degree is high, such that semi-
continuous operation can be realized. No 
organic solvent pollution is caused, and the method is environment-friendly. The method has low integral operation 
energy consumption, and is economical and feasible.