NOVELTY - Extracts of solanine are prepared from potatoes by crushing, drying and grinding 100 g modified potato into powder; performing solvent extraction using methanol/water/acetic acid solution and using low frequency ultrasonic auxiliary extraction; filtering the obtained solution, collecting precipitate, and vacuum freezing and drying to obtain crude product; and performing sub-critical water extracting on crude product using super-pure water as solvent and 10-30% ethanol as entrainer, extracting at 10-15 MPa and 150-180 degrees C for 10-20 seconds, adding ammonia water, and collecting precipitate.    USE - Method for preparing extracts of solanine from potatoes (claimed).    ADVANTAGE - The method uses subcritical water extraction which has low cost and no pollution, and is green and environment-friendly.    DETAILED DESCRIPTION - Preparation of extracts of solanine from potatoes comprises (A) crushing, drying and grinding 100 g modified potato into powder; (B) performing solvent extraction using methanol/water/acetic acid solution at a ratio of 400/100/50 v/v/v, and using low frequency ultrasonic auxiliary extraction at 20-50 kHz and 100-500 W for 30-50 minutes; (C) filtering the obtained solution, vacuum concentrating, dissolving concentrate in 30-50% methanol, adding ammonia water for adjusting solution pH value to 8-10, stirring at 5000 rpm for 30 minutes, collecting precipitate and using water to wash for 2-3 times, stirring at 5000 rpm lower centrifugation, performing sedimentation with microwave, vacuum freezing and drying to obtain crude product (I); (D) performing sub-critical water extracting on crude product (I) using super-pure water as solvent and 10-30% ethanol as entrainer, extracting at 10-15 MPa and 150-180 degrees C for 10-20 seconds, adding ammonia water for adjusting solution pH value at 8-10, stirring at 5000 rpm for 30 minutes, collecting precipitate and using water to wash for 2-3 times, stirring at 5000 rpm, performing sedimentation with microwave, vacuum freezing, and drying to obtain crude product (II); (E) dissolving 2-3 g solanine crude product in 100 ml ethyl acetate, adding 200 ml of 100% methanol and sodium carbonate, shaking to mix, standing and layering, taking solution, adding 150 ml ethanol/water/acetic acid at a ratio of 400/100/50 v/v/v solution, and filtering; and (F) performing microwave vacuum freezing and drying to obtain solanine.