The low chemical reactivity of bauxite residue (BR) has significantly limited its effective utilization, leading to widespread disposal and severe environmental pollution. In semi-arid regions, dispersive soils threaten the stability of silt retention dams, which are vital for controlling erosion. To enhance the utilization of BR and mitigate the dispersibility of dispersive soil, this study employed thermal activated BR to treat both artificially prepared and natural dispersive soils. The stabilizing effects of thermal activated BR on dispersive soil were evaluated using dispersibility identification tests, mechanical tests, and particle size analyses. The stabilization mechanisms were further examined through chemical, microscopic, and mineralogical tests. Results indicate that incorporating 2 % thermal activated BR effectively controls the dispersibility of both dispersive soils, increasing their unconfined compressive strength (UCS) and Brazilian tensile strength (BTS) by up to 426 % and 167 %, respectively. During the initial reaction period (0-3 days), the abundant calcium and aluminum ions precipitated by the BR rapidly reduce the thickness of the water film around the clay particles, while the BR powder fills the voids between soil particles. As the reaction progresses, hydroxide ions are continuously released, peaking at 7 days (pH 11.33), triggering a vigorous carbonation reaction. The resulting calcium carbonate fills and cements the soil particles. In the later stages of the reaction (14-28 days), carbonation and hydration reactions occur simultaneously, binding numerous particles <= 0.075 mm into sand-sized particles, thereby significantly enhancing the soil strength and water stability. The validation tests of naturally dispersive soils in this study provide guidance for the resource utilization of BRs and the improvement of dispersive soils.