Abstract: The implementation of zero liquid discharge(ZLD) of fossil-fired power plants is becoming inevitable in compliance with the national environmental policy. ZLD of fossil-fired power plants is divided into two stages, i.e., advanced water-saving and terminal wastewater solidification. This article analyzes the advanced water-saving technical routes and proposes the existing problems in various types of power plants. Meanwhile, the article conducts the technical and economical comparison on the current terminal wastewater solidification methods. By taking account of multiple influencing factors, such as ultra low emission of flue gas pollutants, desulfurization process water quality, desulfurization wastewater quality and quantity, corrosion and fouling of circulating water system, etc., the article also puts forward some suggestions on the determination of ZLD route for fossil-fired power plants.