Abstract: The extraction condition of protein from Chuanminshen violaceum by ultrasonic extraction was optimized by single factor experiments and response surface methodology. The results showed that all investigated parameters had a notable effect on the extraction yield of protein and could be ranked in decreasing order of importance in their effects as follows : extraction temperature, solid- liquid ratio, ultrasonic action time and ultrasonic power. The optimum conditions for extracting protein from Chuanminshen violaceum were determined as follows:p H12.5, liquid-solid ratio (m L/g) 24∶1, ultrasonic power 185 W, extraction temperature 34℃, ultrasonic action time 31 min. Under this condition, the average rate of extraction of polysaccharides was 54.62%. The established regression model describing the extraction yield of protein as a function of four extraction parameters was highly significant (R2=0.9484) . The predictive and experimental results were found to be in good agreement. Thus, the model was applicable for the prediction of protein yield.