The electro-deionization (EDI) system is responsible for the water preparation process' final procedure. Failure of EDI may not only affect the water quality and production capability, but also lead to undesired outage of the associated water production equipment; consequently, the whole plant may even have to be shut down. In this paper, we firstly analyzed the problems encountered by the EDI operating in one power plant thoroughly; then, solution measures were proposed. This work can provide valuable reference for similar EDI systems in other power plants.