Abstract: 【Objective】 This study is to optimize ultrasonic extraction conditions of total flavonoids in NGC fibers,in the hope of providing the basis for reasonable utilization and identification of NGC fibers. 【Methods】 The NGC fibers were used as raw materials and were utilized for total flavonoids extract by ultrasonic cavitation effect to accelerate the dissolution of flavonoids in ethanol,to optimize the experimental conditions with Box-Benhnken center combination principle and response surface design. 【Results】 The optimal extraction conditions were as follows:solid-liquid ratio of 1∶50 g/mL,ethanol concentration of 50%,and extraction time of 50 min.Under these conditions,the average yield of total flavonoids was 5.25%,which was the best condition for the extraction of total flavonoids from NGC fibers by ultrasonic method. 【Conclusion】 The optimal condition Parameter for ultrasonic extraction of total flavonoids from green cotton fibers is a liquid to material ratio of 1∶50 g/mL,ethanol concentration 50%,extraction time 50 min,obtaining an average total flavonoid yield of 5.25%.