This dataset is Supporting Information for MS #2020EF001516 entitled “Spatially explicit inventory of sources of nitrogen inputs to the Yellow Sea, East China Sea and South China Sea for the period 1970-2010” in Earth's Future.The Supporting Information provides other details besides the main text to support this study, including statistical data on population and food production, method schemes, model validation results, information on the study area, modelled results of nitrogen delivery to surface waters, nitrogen retention loads in river basins and nitrogen inputs from each external source and their spatial distributions in the coast, and reported eutrophication status and red tide outbreaks in Chinese seas. Movies and modelled output data are in separate files and briefly described in this text.