NOVELTY - Extracting and purifying total steroid saponin from Egypt Acorn and separating their monomer involves: oven drying and crushing Egypt Acorn, extracting with supercritical carbon dioxide, collecting total steroid saponin extractive, adding water, diluting, passing macroporous resin, eluting respectively with distilled water and ethanol, collecting eluting liquid, condensing into extract, drying at low temperature to obtain the total steroid saponin, processing high speed counter-current chromatography for separating and purifying the monomer compound.    USE - For extracting and purifying total steroid saponin from Egypt acorn and separating their monomer (claimed).    ADVANTAGE - The method is simple and rapid, easy to control, environmental friendly, and is suitable for large-scale production.    DETAILED DESCRIPTION - Extracting and purifying total steroid saponin from Egypt Acorn and separating their monomer involves: (1) oven drying and crushing Egypt Acorn seeds, placing the powder and assistant into the supercritical carbon dioxide extracting machine with a mass volume ratio of 1- 2, taking the absolute ethyl alcohol as entrainer, adjusting the indexes of the extracting kettle, controlling the temperature of the extracting kettle at 45-65 degrees C and pressure at 30-38 MPa, controlling the carbon dioxide flow at 20-25 kg per hour, controlling the extracting time for 3-4 hours, controlling the separating temperature for 40-50 degrees C, controlling the separating pressure at 6-12 Mpa and collecting total steroid saponin extractive; (2) adding water, diluting, passing macroporous resin, eluting respectively with distilled water and 20% ethanol, eluting with 40-70% of ethanol, collecting eluting liquid, condensing into extract, drying at low temperature and obtaining the total steroid saponin; and (3) processing high speed counter-current chromatography for separating and purifying, refining with crystalline method and obtaining the monomer compound of balanitin 4, balanitin 5 and balanitin 7.