EDI water treatment technology currently in power plant boiler feed water preparation systems more and more common. The main reason is due to the EDI water treatment technology has obvious advantages in terms of environmental protection. However, during operation to ensure that the equipment is running well and boiler water effluent quality to meet the requirements, but also the factors affecting the operation of enough attention. Through the analysis of the actual operation characteristics of EDI case of water treatment technology and application notes were simply described.