NOVELTY - Preparing sodium aescinate comprises (i) extracting Chinese buckeye seed as raw material using ethanol solution; (ii) subjecting the extract solution to high-speed centrifugation, and ultra-filtering; (iii) recovering extraction solvent, adding water to dissolve, absorbing, washing, eluting, and collecting eluent; (iv) recovering solvent from the eluent, adding water to dissolve, collecting effluent, and eluting; (v) combining the eluent and effluent, condensing, adding water to dissolve, regulating pH, adding acetone aqueous solution, stirring, separating precipitate, filtering, and drying.    USE - The method is useful for preparing sodium aescinate (claimed).    ADVANTAGE - The sodium aescinate has high safety.    DETAILED DESCRIPTION - Preparing sodium aescinate comprises (i) taking Chinese buckeye seed as raw material, using 30-70% ethanol solution for extracting, and collecting extract solution; (ii) subjecting the extract solution to high-speed centrifugation, and ultra-filtering through an ultra-filtration film filter with molecular weight cutoff of 10000-15000 Daltons; (iii) recovering extraction solvent from the filter liquor, adding water to dissolve, absorbing through a macro-porous resin column, washing with pure water, eluting with 20-40% ethanol solution and 50-70% ethanol solution elution, and collecting eluent of 50-70% ethanol solution; (iv) recovering solvent from the eluent under reduced pressure until there is no alcohol taste, adding water to dissolve, passing through polyamide resin column, collecting effluent, and then eluting with 10-30% ethanol solution; (v) combining the eluent and effluent, condensing under reduced pressure to obtain extract, adding 0.5-2 times of water to the extract for dissolving, using 0.5-5% sodium hydroxide solution to regulate pH value to 8-11, adding 0.5-2 times of acetone aqueous solution, stirring, separating out white precipitate, filtering the precipitate, and drying to obtain the product. An INDEPENDENT CLAIM is also included for sodium aescinate, comprising 30-40 wt.% sodium aescinate A, 15-20% sodium aescinate B, 25-30% sodium aescinate C, and 10-15% sodium aescinate D, where the amount of the sodium aescinate A, B, C and D is 85-90% of the total sodium aescinate.