This paper attempted to separate glyoxylic acid from the system of the electro-oxidation of glyoxal by electrodialysis.The influences of current density，flow velocity，temperature and nature of anion membrane on electrodialysis were studied.The results showed that flow rate at 4.21 cm·s-1，temperature at 30℃，AHT as anion membrane and the process with current density 628.7 A·m-2 at early stage and 456.6 A·m-2at later stage benefitted the separation of the system of glyoxylic acid.