Abstract: Based on the meteorological data obtained from preparatory work of a large-sizeproject--a nuclear power station located in Yangjiang, characteristics of the sea-landbreeze circulation over the coastal area of this region were analyzed. It is shown that the frequency of the sea-land breeze circulation is quite high but the height of some part of that is small; the averaged persistent time lies between 9 to 10 hours; the sea breeze is much stronger than the land breeze; the return-flow in the upper layer is weaker than the inflow near the surface. The structure of the sea-land breeze circulation is special in structure. The pollution in this region will not accumulate because of the big angles between the wind directions of upper return-layer and lower layer.