An electrodialysis operation was performed to remove total dissolved solids (TDS) from polymer-flooding wastewater. The influence of flow rate and electrical potential on rate of TDS removal was studied during electrodialysis operation. Removal rate of the main ions in polymer-flooding wastewater is: Ca2+>Cl->Na+>HCO3-; From the economical viewpoint, energy consumption increases greatly, and electrical potential increased for the same flow rate, but the influence of flow rate on energy consumption was not evident. The researchers studied electrodialysis technology to remove TDS of oily wasterwater and achieved closed circulation of polymer-flooding water in crude oil extraction.