Based on a one-dimensional saturated soil column experiment, this paper used the experimental data to calibrate and validate the SUTRA model, and conducted long-term sequence simulations of the vertical migration process of salt under density-driven conditions under different concentrations, different soil textures, and different depths of impermeable bottom plates. The simulation results proved that the vertical migration of salt is significantly affected by density: when 100 g/L salt solution was input at the top of the quartz sand column, the traditional pure diffusion simulation of salt vertical migration was slow, and only 10 cm downward migration occurred after 1 day, which was inconsistent with the measured results; while considering density-driven simulation, the speed of salt vertical migration was significantly accelerated, and it could reach the bottom and gradually accumulate within 9 hours, which was more consistent with the measured situation. Soil texture had a significant impact on the speed of salt density-driven migration. The downward migration speed of salt in silty loam soil was significantly slower than that in quartz sand. At the same time, as the migration process progressed, the salt content gradually decreased in the upper layer while continuously increased in the lower layer of the soil column, and eventually tended to be uniformly distributed, forming a high-salt zone of groundwater. When the depth of the impermeable bottom plate was 90, 150, and 200 cm, the time required for the distribution to become uniform gradually decreased to 10, 20, and 30 years respectively, indicating that the deeper the impermeable bottom plate, the longer the time required for the distribution to become uniform. This research to some extent reveals the long-term balance and evolution laws of soil salinization in irrigation areas under density-driven conditions, and can provide new ideas and theoretical basis for the sustainable utilization of water and soil resources and the effective control of soil salinization in irrigation areas.