Abstract: Thermal discharge is an important factor to be considered in the environmental impact assessment, the determination of water intake and discharge projects and the feasibility study of the nuclear power plant projects.In this paper, several important issues related to the heat dissipation characteristics of thermal discharge in water intake and discharge engineering of coastal NPPs are studied and discussed.Combined with the design of water intake and drainage engineering, the simulation of temperature and drainage and the prototype observation of temperature field in some coastal NPPs in China, the changes of water temperature along the open channel or tunnel, the delay of recirculation on the shore, the calculation of sea surface heat dissipation, and the submerged deep drainage are discussed.The article also summarizes the contents that need to be improved in the current research, and gives some methods to further optimize the design and scientific research related to thermal discharge.