Abstract: The discharge of the thermal water and radioactive liquid effluents in coastal nuclear power plant cooled by direct flow circulating share a same outfall that is called the main discharge outfall. So the discharge outfall layout should meet the emission regulations of thermal water and radioactive liquid effluents. For discharge mode selection, besides the heat environmental capacity of receiving water, beach type and applicable disposal degree, temperature rise limit and technological and economic indexes, it is also closely related with discharge outfall location and tide types of receiving water. In the light of a non-regular semidiurnal tide, the radioactive liquid effluent discharge mode and the main discharge outfall setting are analyzed, and then some positive suggestions are given on the basis of some laws and regulations and the situation of the nuclear power plants in China.