Abstract: The effects and principles of the three main factors ( time of operation, liquid ratio and ultrasonic power) for extraction of polysaccharides in chestnut shell with ultrasonic power was studied.Experimental factors' levels were determined by single- factor experiments. The Center Composite combination ( Center Composite Design, CCD) experimental design with three levels of three factors of response surface analysis was used to optimize the extraction conditions.The results showed that the optimal extraction technological condition of polysaccharides from chestnut shell was as follows: the ultrasonic power was 165W, ultrasonic time was 27min and material- liquid ratio was 1∶62.Under this condition, the ultrasonic extraction of polysaccharide in chestnut shell was the best.The yield of the polysaccharides was 11.48%.