To establish the extraction technology of cellulase assisted by ultrasonic wave of Momordica charantia polysaccharides (MCP), the optimization was applied to discuss some factors including ultrasound power, enzyme amount, the ratio of solid to liquid, extracting time, pH value, temperature with BoxBehnken centerunited design and the method of response surface analysis (RSM). Through establishing the second regression model, the optimal parameters were conformed as follows: ultrasound power 390W, cellulase amount 3500U/g (enzyme activity was more than 200U/mg), ratio of solid to liquid 1∶38, extracting time 40min, pH value 5, temperature 56℃. Then the yield of crude Momordica charantia polysaccharides is 21.1%, higher 7.8%, 13.5% and 7.7%, respectively, comparing with the specific heat of flooding, ultrasonic wave and cellulase. These results suggested that cellulase assisted by ultrasonic wave extraction technology was one of the effective ways to improve the yield of Momordica charantia polysaccharides. 