Objective:To maximize flavonid extraction yield,optimization of the extraction of total flavonoid from clerodendranthus spicatus under ultrasound assistance was achieved by response methodology.Methods:On the basis of single -factor experiments,Box-Behnken design(BBD) involving three variables at three levels was utilized to set up a quadratic polynomial regression equation.Extraction temperature,ethanol concentration and liquid/material ration, and pair-wise interactive effects of above three variables on their function were investigated by response surface analysis.Results;The optimum condition were;30min ultrasound treatment at 100%power,ethanol concentration 54%,liquid and solid ratio was 20:1,extracting temperature 70℃.Conclusions:Under these optimum conditions, the yield of total flavonoid was 7.6%.