NOVELTY - Producing L-ornithine-L-aspartate, comprises (i) mixing L-ornithine salt with deionized water, adding anion exchange resin, agitating to obtain mixed solution and detecting the content of chlorine ions; (ii) adding aspartic acid into L-ornithine salt, agitating, filtering, controlling reacting temperature and concentrating the filtrate to obtain concentrated solution; and (iii) adding activated carbon into the concentrated solution, filtering the solution, heating the filtrate, adding absolute ethanol, cooling the filtrate until crystals are generated, filtering and drying the crystals.    USE - The method is useful for producing L-ornithine-L-aspartate.    ADVANTAGE - The method: does not produce waste gas or waste dreg, and chemical oxygen demand and biochemical oxygen demand; does not pollute the environment; does not use poisonous raw materials; produces very less amount of wastewater; and exhibits high yield rate (over 80%) and high quality.    DETAILED DESCRIPTION - Producing L-ornithine-L-aspartate, comprises (i) mixing L-ornithine salt with deionized water according to mass ratio of 1:(2-20), agitating the materials for 1-2 hours until L-ornithine salt dissolves completely, adding anion exchange resin, agitating continuously to obtain mixed solution and detecting the content of chlorine ions by using silver nitrate solution; (ii) adding aspartic acid into L-ornithine salt according to mass ratio of (0.8-1.2):1, after chlorine ions of the mixed solution are absorbed thoroughly, controlling reaction temperature at 40-100 degrees C, agitating for 1-10 hours, filtering the solution to remove resin, controlling reacting temperature at 40-90 degrees C and concentrating the filtrate to 0.5-1.5 g/ml concentration to obtain concentrated solution; and (iii) adding activated carbon into the concentrated solution to decolorize the filtrate for 20-60 minutes, controlling mass ratio of activated carbon to L-ornithine salt at (0.01-0.1):1, filtering the solution to remove activated carbon, heating the decolorized filtrate at 50-80 degrees C, dropwise adding absolute ethanol into L-ornithine salt according to mass ratio of (1-2):1, cooling the filtrate to room temperature until crystals are generated, filtering and drying the crystals at 45-75 degrees C for 8-30 hours to obtain the product.