Abstract：Ultrasound-assisted cellulase was used to extract polysaccharides from Sparassis crispa，optimize the experimental design and determine the best extraction conditions．This paper conducted a singlefactor experiment on 5 factors，including ultrasonic power，ultrasonic time，ultrasonic temperature，material-to-liquid ratio，and amount of cellulase added．It was confirmed that under the conditions of 570 W ultrasonic power and 3% cellulase added amount，the material-to-liquid ratio，ultrasonic time，and ultrasonic temperature were used as 3 interactive factors to carry out Box-Behnen experimental design and response surface optimization．The best solution was as following：the material-to-liquid ratio was 1∶87.62（g · mL-1），ultrasonic temperature was 38.4 ℃，and ultrasonic time was 94.56 min，then the predicted polysaccharide yield could reach 31.49%． After verifying the best forecast model paramter，the results showed that under the conditions of material-to-liquid ratio 1∶90 （g · mL-1），extraction temperature 38 ℃，extraction time 95 min，the extraction rate of crude polysaccharide from 5 g Sparassis crispa powder could reached as high as 30.6%．The crude polysaccharide extraction was also performed on 50 g Sparassis crispa powder．The first extraction rate was 31.70%，and the second extraction rate was 7.1%．After concentrating the extracted crude polysaccharide，deproteinizing，depigmenting，and purifying by dialysis，the polysaccharide retention rate was 73.20%．
