The National Development and Reform Commission of China has approved a large number of nuclear power projects, with a total capacity of 23,000 MW. However, concomitant with the accelerated development of nuclear power stations, the environmental effects of thermal discharge will become a problem that cannot be avoided. Real-time monitoring of water temperature needs to be installed following station construction in order to measure its variation with time and to ensure that the operation of the nuclear plant does not result in adverse environmental damage. Landsat is the world’s oldest, continuously acquired collection of space-based, moderate-resolution, land remote sensing data. On May 30, 2013, data from the Landsat 8 satellite became available, and the data quality and radiometric quantization of the thermal infrared sensor (TIRS) are significantly greater than those of previous Landsat instruments. The analysis of sea surface temperature (SST) obtained from Landsat 8’s TIRS data was used to enhance information about the plume shape, dimensions, and direction of dispersion of the thermal discharge from the Qinshan Nuclear Power Plant in Hangzhou Bay on the East China Sea coast. Both single-channel and split-window algorithms were used and focused. The detection of temperature increases through split-window algorithms is considered a preferable method for warm discharge monitoring. Recent results showed that the thermal discharge from the nuclear plant was controlled over a small area, and that it never breached national water quality standards.