The spatial distribution of water-salt is different in saline-alkali soils under different afforestation trees. The effects of different afforestation trees on soil water-salt distribution and saline-alkali soil properties were studied through using field investigation and indoor detection in Ningxia. The results show that: 1) In Salix psammophila plot, the further from the trunk, the higher topsoil moisture is, and salt is accumulated in 20-60 cm soil layer away from the tree trunk. Soil moisture is significantly lower in 60-100 cm layer in Tamarix chinensis plot than in other layers, soil moisture is the lowest in 40-80 cm layer in Salix matsudana ‘9901’ plot, salt is accumulated below 60 cm layer in Tamarix chinensis and Salix matsudana ‘9901’ plots. 2) Topsoil moisture is moderate variation under three afforestation trees and weak variation in other layers. Soil salinity are moderate variation in Salix psammophila and Salix matsudana ‘9901’ plots, moderate variation in 0-40 cm layer in Tamarix chinensis plot, and weak variation in layer below 40 cm. 3) Planting trees can reduce soil pH and bulk density, and the effects are more obvious when the trees are closer to the trunk. Soil pH and bulk density of the three trees show weak variation and relatively uniform spatial distribution. The results reveal the influence of different afforestation trees on soil water-salt distribution in saline-alkali soil, which is of significance for the restoration of vegetation in saline-alkali land.