Abstract: Due to the certain gap between the current situation of water discharge and the exact requirements of pollutant discharge permit system in thermal power plants, it is imperative to enforce the regulations for wastewater discharge control. After listing the related laws and regulations of water saving and standards, based on the actual situation of water discharge, this paper put forward the technology route of water discharge control specifically, which included the water control target and principle as well as the technology routes for raw water pretreatment, desulphurization wastewater treatment and other types of wastewater treatment. In addition, the technical route of terminal wastewater treatment is presented, which can provide the beneficial reference and thoughts for the relevant transformation of thermal power plant.