NOVELTY - Preparing leuprorelin acetate comprises preparing N-(tert-butoxycarbonyl)-L-proline-cesium (Boc-Pro-Cs) solution, adding Boc-Pro-Cs to chloromethyl-polystyrene (Cl-CH2-P resin) (II), reacting, filtering, washing resin, baking to obtain N-(tert-butoxycarbonyl)-L-proline-polystyrene resin, preparing raw material, connecting dipeptide to nonapeptide, removing the blocking group, neutralizing, detecting free ammonia to obtain leuprorelin acetate nonapeptide resin, performing aminolysis, purifying to obtain leuprorelin acetate intermediate purified product, condensing, filtering and lyophilizing.    USE - The leuprorelin acetate is useful for preparing medicine for treating precocity, endometriosis, uterine fibroid or pre-menopausal breast cancer and/or prostate cancer in females (claimed).    ADVANTAGE - The method is environment-friendly and safe, and produces product with high purity and yield.    DETAILED DESCRIPTION - Preparing leuprorelin acetate comprises: (i) preparing by adding methanol solution of N-(tert-butoxycarbonyl)-L-proline-polystyrene resin (Boc-Pro-P) (I) to the cesium carbonate aqueous solution of to obtain N-(tert-butoxycarbonyl)-L-proline-cesium (Boc-Pro-Cs) solution, condensing and evaporating solvent to obtain solid, adding methanol, vacuum evaporating, vacuum drying to a constant weight, adding anhydrous dimethylformamide solvent to Boc-Pro-Cs, heating to dissolve, adding Boc-Pro-Cs to chloromethyl-polystyrene (Cl-CH2-P resin) (II), stirring, reacting, filtering, washing resin, and baking and vacuum drying to obtain (I); (ii) preparing raw material, connecting dipeptide, tripeptide, tetrapeptide, pentapeptide, hexapeptide, heptapeptide, octapeptide and nonapeptide, removing the blocking group, washing, neutralizing, repeatedly washing, connecting peptides and detecting free ammonia to obtain leuprorelin acetate nonapeptide resin; (iii) performing aminolysis by separating leuprorelin acetate from leuprorelin acetate nonapeptide resin using ethylamine to obtain leuprorelin acetate crude product; (iv) purifying by HPLC to obtain leuprorelin acetate intermediate purified product; (v) condensing; and (vi) filtering and lyophilizing. An INDEPENDENT CLAIM is also included for a leuprorelin acetate product prepared by the above mentioned method.