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• The contribution of Pu from PPG close-in fallout in some samples is 41.5–50%. • Pu from the ocean to the coast is mainly controlled by ocean currents and tides. • The migration of Pu can be explained by the idea of "source-sink". • The distribution of Pu in coastal areas reflects the "land-sea interaction". 239Pu, 240Pu in the surface sediments from tidal flat wetlands in northern Jiangsu Province and radial sand ridge in southern Yellow Sea were analyzed by SF-ICP-MS. Tidal flat wetlands and radial sand ridge are the special sediment deposits in coastal area, which are the ideal places to study "land-sea interaction". The 240Pu/239Pu atom ratios in our research samples show that the Pu in most samples is from global fallout, only the Pu in a few samples near Yangtze River Estuary and channel of radial sand ridge is affected by the close-in Pu fallout from Pacific Proving Grounds (PPG), and the contribution of Pu from PPG is 41.5–50%. In composition, since the study samples are mainly sand, the 239+240Pu activities in our samples are lower than those in river sediments of China. The transport of Pu is a very important scientific issue, and researches have shown that Pu is "transported" into the coastal areas and seas from the land- based "source". In addition, the Pu distribution in coastal areas and seas is affected by the input of rivers and ocean currents, which is a manifestation of the "land-sea interaction". [ABSTRACT FROM AUTHOR]