Abstract: To optimize ultrasonic-assisted extraction process of total flavononids from Nardostachys chinensis Batal.On the basis of the single factor test,ethanol concentration, extraction time,ratio of material and liquid,and extraction times were selected for Box-Behnken central composite designing.With extraction yield of total flavononids as response value,the extracting process was optimized by the response surface method(RSM).The optimized extraction conditions were as follows:ethanol concentration was 55%,the extraction time was 35 min,the ratio of material and liquid was 1:35（g/mL）,the extraction times was 3 times.The extraction yield of total flavononids was 39.102 mg/g and the relative error was 3.00% that compared with actual value.The RSM technology optimization for extracting total flavononids from N.chinensis Batal. was suitable.In addition,it can be used to assist the quality evaluation of N.chinensis Batal.

Key words: response surface method, Nardostachys chinensis Batal, total flavononids, ultrasonic extraction optimization