The method for extracting dioscorea saponin from yellow ginger and Japanese dioscorea includes the following steps: washing yield ginger and Japanese dioscorea, breaking them, adding clear water and uniformly stirring them, ultrasonic wave treatment, placing them into cracking tank, adding concentrated hydrochloric acid or sulfuric acid, cracking under the condition of a certain concentration and pressure, adopting sodium hydroxide and potassium hydroxide to neutralize crackate to neutrality, distilling crackate mixture, when the water content is up to 15-40%, discharging material, drying to control water content in 3-8%, and using supercritical Co2 extraction process to obtain dioscorea saponin, and utilizing waste dregs produced after extraction to produce biological organic fertilizer for improving soil structure. |