The separation of ammonium sulfate from dilute solution by electrodialysis was investigated. From the results obtained, it is suggested that it is feasible to separate ammonium sulfate from aqueous solution by electrodialysis. The removal performance of ammonium sulfate obtained was very satisfactory. The optimal cation and anion membranes were found. The removal efficiencies were influenced by voltage, initial concentration, flow rate and temperature. High voltage and high temperature are beneficial to this separation process, but high fluid flow rate and concentrated initial concentration prolong the operation time required to achieve the target value. It was found that the optimal outlet concentration is 1 g/L, since the operation time is prolonged almost two-fold if the outlet concentration is decreased from 1 g/L to 0.5 g/L.