A computer simulation program is developed to predict desalinating performance of a feed and bleed electrodialysis process, inputting membrane characteristics, electrodialyzer specifications and electrodialytic conditions. Computing results enable to discuss the phenomena such as influence of cell voltage on current density, ionic fluxes, solution fluxes, current efficiency, ohmic potential and membrane potential, and further the influence of cell voltage and electrolyte concentration on the output of desalted solutions, energy consumption and water recovery. Excepting limiting current density, the performance of an electrodialyzer is scarcely influenced by the standard deviation of the normal distribution of the solution velocity ratio in desalting cells. Energy consumption in a feed and bleed process is larger than that in a batch process for higher feed concentration, and it is less than that in a reverse osmosis process at feed concentration less than one thousand and hundred-odd mg/l. (C) 2009 Elsevier B.V. All rights reserved.