Abstract：Riverine phosphorus （P） content is one of key indexes of water quality. Global and regional riverine P cycle relating to riverine P content is well-established， however， identifying the sources and quantifying the contribution of individual P sources from watersheds to streams and rivers is still not well known. P fluxes from three sources of phosphorus ore， phosphorus chemical industry， phosphogypsum reservoir， so-called “three-P”， are potentially substantial， but the loading and source contribution from three-P are unclear in recent decades. We modeled P loads into the river network， riverine P retention， and riverine P fluxes at key stations by using land use data with high resolution （100 m ×100 m）， P biogeochemical budgets， Strahler river model， as well as nutrient “spiraling” theory. We reported results from in-situ measurements of P concentration to characterize P fluxes for two years （2016—2017） in the Changjiang River. These measured data are used to validate the global NEWS-total P biogeochemical model from the eleven sub-basins along the Changjiang River. The average amounts of P loading into the river network are about 52.0×107 kg P， corresponding to （285.19±23.38） kg·km-2·a-1， during the period of 2010 to 2017. We further modeled P loads from “three-P” sources into the river network for source contribution. Our integrated P model simulation demonstrates that three-P loads increased from 9.23×107 kg P in 2010 to 26.57×107 kg P in 2017. The magnitude of “three-P” yields is comparable to yields modeled for agricultural nonpoint source of P across sub-watersheds. These high “three-P” yields constitute an unprecendented non-point source to riverine fluxes. Multi-scenarios analysis suggests that scenarios 3， 4 and 9 are effective and practicable to be recommended as favorable choices in controlling and managing the Changjiang River P pollution.