NOVELTY - Ultrasonic wave-assisted aqueous two-phase extraction of total dioscin includes cleaning yam, removing musty and rotten part, slicing, drying to constant weight, crushing the dried sample, uniformly shaking, and sealing; preparing aqueous two-phase system having n-butyl alcohol concentration of 15-52 wt/wt.% and ethanol concentration of 13-17 wt/wt.%, weighing yam powder, and adding to the aqueous two-phase system; ultrasonic wave-assisted extracting; and centrifuging the extracted solution and collecting the upper phase solution and lower phase solution.    USE - Ultrasonic wave-assisted aqueous two-phase extraction of total dioscin (claimed).    ADVANTAGE - More than 32 mg of diosgenin is obtained per gram of dry yam powder; and purity is greater than or equal to 90%. The recovery rate is greater than 85%. Compared with the traditional acid hydrolysis and Soxhlet extraction, the method has mild condition, low acid use, and low pollution; achieves rapid extraction; and is easy for industrial preparation. Compared with the salt/short chain alcohol aqueous two-phase extraction, the method has complete extraction, recoverable upper phase solvent and lower phase solvent, and high efficiency; and is green and environmentally friendly.    DETAILED DESCRIPTION - Ultrasonic wave-assisted aqueous two-phase extraction of total dioscin comprises cleaning yam, removing musty and rotten part, slicing, drying in an oven having temperature of 60 degrees C to constant weight, crushing the dried sample to 200-mesh by a crusher, uniformly shaking, and sealing; preparing aqueous two-phase system having n-butyl alcohol concentration of 15-52 wt/wt.% and ethanol concentration of 13-17 wt/wt.%, weighing yam powder, and adding to the aqueous two-phase system, where ratio of material to liquid is 0.05 g/ml; ultrasonic wave-assisted extracting for 30-70 minutes at 20-50 degrees C, where ultrasonic power is 200-300 W and ultrasonic frequency is 20-80 Hz; centrifuging the extracted solution, and collecting the upper phase solution and lower phase solution to obtain alcoholic solution containing total dioscin; heating, concentrating, and recovering alcoholic solution at 70-120 degrees C; and drying at 60-100 degrees C to obtain total saponins.