Different types of land use have a greater impact on phosphorus pollution in water bodies. In order to explore the impact of land-use change on phosphorus pollution in water bodies, this paper takes the Huazhou Station control basin of Jianjiang River in China as the research object. It uses the SWAT model to carry out a simulation study. Through the simulation analysis of total phosphorus pollution changes under three land-use scenarios, this paper reveals the temporal and spatial distribution of total phosphorus in watersheds under different land-use scenarios. The results show that: 1) The constructed SWAT model can better simulate and analyze the changes of runoff and total phosphorus in the study area. 2) The rainy season is the key period to control pollutants in the watershed of the study area, and agricultural land is the key area to control total phosphorus pollution in the watershed. 3) In the future land use planning of this area, it should occupy as little forest land as possible, and at the same time, reduce the output of total phosphorus from agricultural land through the adjustment of planting structure and the implementation of protective measures. This study can provide research ideas for land use and pollutant control. It can provide theoretical support for protecting and improving the water environment and water quality in the basin.