Coal-fired thermal power plants are an important part of the power industry. There are many uses of water in the power industry, including boiler supplemental water, cooling water, and domestic fire-fighting miscellaneous water. The most stringent requirement for water quality is boiler supplemental water. Nowadays, thermal power plants are developing towards large capacity and high parameters, and the water quality of boiler water is getting higher and higher. The boiler feed water quality requirements are very strict, so in addition to conventional coagulation and precipitation In addition to water treatment methods such as filtration, ion exchange, reverse osmosis, electrodialysis and other softening, desalination and other pure water preparation technologies.