Fermentation mother liquor,as the by-product generated in the production process for amino acids,contains a large amount of organic material residual,salts as well as a small amount of soluble amino acids. In order to provide feasible methods in industrial wastewater treatment,our research aimed to determine the optimum condition of desalination of amino acid fermentation mother liquor based on the electrodialysis in different conditions,such as different flow and current density. It was concluded in this study that higher current density leaded to lower recovery of tryptophan and higher desalination rate when current density was between 10 and 25 mA / cm2. When the flow was from 20 to 60 L / h,larger flow leaded to lower recovery while the influence on desalination rate changed in different stages. When current density was 15 mA / cm2and flow was 20 L / h,it came to the optimum condition of the experiment.