The invention discloses a method for preparing high-purity glufosinate-ammonium by adopting an organic alkali deacidification method, belonging to the technical field of preparation of the glufosinate-ammonium. The method comprises the following steps: by taking glufosinate-ammonium hydrochloride as a raw material, dissolving the glufosinate-ammonium hydrochloride into alcohol R1OH, and thermally filtering out inorganic salt and mechanical impurities; partially concentrating the filtrate, adding organic alkali R2R3R4N for a deacidification reaction, cooling and filtering out glufosinate-ammonium free alkali; adding a crude glufosinate-ammonium free alkali product into the alcohol R1OH, introducing ammonia gas, cooling and filtering to obtain a glufosinate-ammonium product; and recycling an alcohol solvent from crystallization mother liquor of the free alkali, subsequently adding into an inorganic alkaline water solution for neutralization, separating out the organic alkali in the upper layer and directly using the organic alkali in the deacidification reaction. The method disclosed by the invention can be used for effectively removing a small amount of inorganic matters including ammonium chloride, sodium chloride, the mechanical impurities, hydrogen chloride and the like from the glufosinate-ammonium hydrochloride, also can be used for simply and conveniently preparing a high-purity glufosinate-ammonium product without introducing new impurities and organic byproducts and has good industrial application prospects.