Abstract: A coastal nuclear power plant located at the estuary of the Pearl River.Anti-fouling coatings is used to prevent adhesion of foulings on the surface of water intake structures.Based on the prediction model recommended by ISO for Cu²⁺ release rate and the conservative diffusion parameters from numeric model, this paper predicts the Cu²⁺ concentration in the sea water during the operation of the plant.The result shows that the average envelope area for Cu²⁺ concentration great than 8.2 μg/L during fortnightly is 3.98 km².The result meets the requirement of national regulation.Proposals on improving environmental impact assessment of the anti-fouling coatings and mitigating environmental impact are put forward on the aspect of the selection of marine engineering project and anti-fouling coatings, routine environmental monitoring.