To investigate the impact of different installation conditions of rectification curtains on the crucial driving factors of algal blooms in the tributary bay of a river-type reservoir, numerical simulation methods were used. By taking the Xiangxi River, a tributary bay of the Three Gorges Reservoir, as an example, a three-dimensional hydrodynamic and water temperature model was constructed to simulate and compare the changes in flow field and water temperature characteristics of the tributary bay under conditions before and after the installation of a rectification curtain, as well as under different installation positions and submerged depths. The results indicate that the rectification curtain has a significant blocking effect on water flow. Water mass mixing occurs at the upper layer at the section where the rectification curtain is installed, resulting in a decrease in water temperature on the upstream side and a reduction in water temperature stratification. Under different installation positions of the rectification curtain, the flow velocity in the middle layer of the water body changes more significantly as affected by the rectification curtain than that in the surface and the lower layers. Furthermore, when the rectification curtain is installed closer to the upstream of the tributary bay, the influence on flow velocity at the estuary is more significant. However, the effect of the rectification curtain on water temperature has little correlation with its installation position. The average temperature difference across different layers at the rectification curtain section increases with increasing submerged depth. The upper layer exhibits the largest water temperature variation. The depth range of water temperature change also expands with increasing submerged depth, ultimately achieving a reduction in water temperature across the entire vertical section.