Abstract: In order to study the temporal and spatial distribution of phosphorus pollution in Tuojiang River basin, taking Tuojiang River Basin as the research object, the SWAT model was constructed to simulate the migration process of different forms of phosphorus on land, and the spatial and temporal distribution characteristics of the pollution load of phosphorus discharged from land source into the river were analyzed.The results showed that the SWAT model had a good simulation effect.In 2018, 13 433 tons of terrigenous phosphorus entered the Tuojiang River Basin, with non-point source contribution accounting for 97% and granular phosphorus entering the river accounting for 61%.The monthly amount of phosphorus into the river increased with the increase of rainfall, mainly in the form of dissolved phosphorus in August to November, and mainly in the form of particles in other months.The main input areas of phosphorus elements in the river basin were concentrated in the upper reaches of Deyang City and Chengdu City, especially in the months with the lowest discharge, the impact of point source pollution on this area was far greater than other places.In the month of maximum discharge, the phosphorus input showed a more uniform distribution trend in the middle and lower reaches, and the input quantity was larger along the river network line.At the same time, the surface soil showed a strong interception effect on the phosphorus emission from the land, and the phosphorus released from the soil had a relatively small impact on the phosphorus content in the river.