A membrane capacitive deionization (MCDI) system, the one that ion-exchange membranes were added onto a capacitive deionization (CDI) system, has been developed to test desalination performance for power plant wastewater. Several experiments were conducted to compare the MCDI with the CDI in desalination capacity and to determine optimal operation conditions using 1,000 ppm NaCl solution. Salt removal rate of the MCD1 system was 19% higher than that of the CDI system. The flow rate and the direct current voltage at which the salt removal rate was the highest were 40 ml/min and 1.2 V, respectively. Desalination performance for the power plant wastewater was investigated at the given operation conditions. The maximum salt removal rate and electric energy consumption were about 92% and 1.96 Wh/L, respectively. It was concluded from this study that the MCDI system could successfully be applied for the reuse of power plant wastewater.