The invention discloses a preparation method of an arginine ibuprofen salt. The method is that ibuprofen is adopted to dissolve into ethanol with 95 percent concentration and added with solid arginine while stirring, and then heated to 40 to 80 DEG C, stirred for 15 to 60 minutes, after reaction, cooled to room temperature and crystallized. The preparation method of the invention adopts that the solid arginine is directly added to the ibuprofen solution and no solvent is added before the solid arginine addition, thus shortening production technique steps and reducing reaction equipment. The process that directly crystallization from mother liquid in room temperature, need not be added with other solvent to dilute, thus reducing consumption of solvent and kinds, shortening production technique flow; as the solvent can be recycled and reused, thus reducing production cost and saving energy.