Abstract: Purple sweet potato powder and low gluten flour were used as the main raw materials in this experiment.The addition of purple sweet potato powder,white sugar,edible oil and egg yolk were taken as independent variables.On the basis of the single- factor test and according to Box- Benhnken design,the interaction of independent variables and their influence on sensory evaluation score of purple sweet potato biscuits were investigated. The production forum of purple sweet potato biscuits was optimized by response surface methodology.The results also showed that the optimum parameters of the experiment were purple sweet potato powder 10.70 g,low gluten flours 39.30 g,white sugar 18.64 g,edible oil 10.03 g,egg yolk 8.26 g,baking powder0.5 g and the amount of water.The biscuits were of the best quality under the baking temperature of 140 ℃ for10 min. They were agreeably sweet,crisp,uniformed in surface color without burning.