Objective: To optimize extraction process of total phenolic acids from Crepis turczaniowii. Method: Based on single factor tests

central composite design-response surface methodology was adopted to optimize extraction process of total phenolic acids from C. turczaniowii

independent variables were ethanol concentration

reflux time and solvent folds

dependent variable was extraction rate of total phenolic acids.Linear or no-linear mathematic models were used to estimate relationship between independent and dependent variables

optimum extraction process was optimized

then prediction was carried out through comparing the observed and predicted values.The content of total phenolic acids was determined by UV. Result: Optimum extraction technology conditions were:extracted 3 times with 35 times the amount of 70% ethanol for 55 minutes each time.Regression coefficient of binomial fitting complex model was as high as 0.936 9

bias between the observed and predicted values was -2.28%. Conclusion: Optimum extraction process was reasonable

stable and feasible

it was suitable for development and utilization of total phenolic acids from C. turczaniowii.