The serious problem of soil salinization restricts the sustainable and high- quality development of agriculture in arid and semi- arid regions of China. Understanding the distribution characteristics and vertical migration mechanism of soil salt ions in the vadose zone is of great significance for the scientific prevention and control of soil salinization. Methods: By conducting fine- grained sampling of the 2 m depth profile soil in the Yanqi Basin, the mechanical composition and content of eight salt ions in the samples were determined. The fractal dimension of soil particles was calculated, and statistical methods were used to analyze the vertical distribution characteristics of soil salt ions in the vadose zone. Additionally, the relationship between soil texture and water—salt transport in the vadose zone was explored.Results:The results showed that the vadose zone soil in the Bohu profile was mainly non- saline soil. The soil salinity was mainly controlled by the hydrochemical type and mineralization degree of the groundwater in the downstream of Kaidu River. The ratio of cations to anions was approximately 2∶5, and the main salt types were Ca2+—HCO2-3 and Na+—SO2-4. The vadose zone soil in the Yanqi profile is generally heavily saline soil. The soil salinity is comprehensively influenced by the hydrochemical type of the groundwater in the downstream of Kaidu River and the salinity of its own vadose zone. The ratio of cations to anions is approximately 1∶2, and the main salt types are Ca2+—SO2-4 and Na+—Cl-. There is a significant positive correlation between soil fractal dimension and fine particle content, and a significant negative correlation with sand content. There is no significant correlation between soil salinity and fractal dimension in the vadose zone, which is mainly affected by the comprehensive effects of soil particle size composition and its depth. The soil texture of the aeration zone of the Bohu profile gradually becomes coarser from the surface layer to the deep layer. The salt content exhibits a large fluctuation in the surface layer at a depth of 0~80 cm and the bottom layer at a depth of 125~200 cm, and a stable trend of change at a depth of 80~125 cm. The salt ions are mainly concentrated at the interface between the silty clay loam and the silty clay layer at a depth of about 30 cm. The soil texture of the Yanqi profile gradually becomes finer from the surface layer to the deep layer. As the depth increases, both the salt content and the degree of fluctuation gradually decrease. The salt ions are mainly concentrated in the surface soil layer at a depth of 0~10 cm.Conclusions: The transport of soil salt in the aeration zone of Bohu can be roughly divided into three parts: the interaction segment (0~80 cm), the balance segment (80~125 cm), and the groundwater disturbance segment (125~200 cm). The depth affected by evaporation is approximately 80cm. The transport of soil salt in the aeration zone of Yanqi can be roughly divided into two parts: the salt ion ascending segment (0~120 cm) and the balance segment (120~200 cm). The depth affected by evaporation is approximately 120 cm. The soil texture composition of the vadose zone with finer particles on the top and coarser particles on the bottom is an ideal distribution pattern for inhibiting soil salinization. For the Yanqi profile type, irrigation can be used first to suppress salt, followed by plowing to a depth of approximately 40 cm. For the Bohu profile type, deep tillage to a depth of about 50cm can be directly adopted, which can suppress the occurrence of salinization to a certain extent.