Abstract: This study investigated the temperature distribution in the sea area around the Qinshan Nuclear Power Plant using Landsat thermal infrared remote sensing data. The results indicate a strong correlation between the inversion results of temperature and the measured data, suggesting reliable inversion results. Before the operation of the nuclear power plant, the surrounding sea area exhibited relatively uniform temperature, with no significant temperature difference except for natural warming. Furthermore, the temperature along the coast remained almost unchanged in the north-south direction and displayed slight temperature gradients in the east-west direction, with temperature variation not exceeding 0.6 ℃ within 10 km from the coast. After the operation of the nuclear power, the surrounding sea area showed temperature differentiation. The distribution characteristic of thermal discharge was closely related to tides and seasons. In the same season, the increased amplitude of the temperature during ebb tides generally exceeded that during flood tide. Under the same tidal condition, the increased amplitude of the temperature in summer typically exceeded that in winter. At a certain water intake of the first plant, the surface seawater manifested a temperature rise of over 1.0 ℃ during flood tide. Landsat data generally meet the demand for research on temperature distribution in the surrounding sea area of the Qinshan Nuclear Power Plant, and the distribution of thermal discharge under specific tidal conditions can be investigated using aerial remote sensing monitoring.