Abstract: In order to determine the potential for vegetation rehabilitation and set the goal of soil and water conservation forest in water-shortage region of Loess Plateau,16-year-old artificial Caragana korshinskii Kom stand grown in a reasonably uniform site was selected and thinned to establish different densities of experimental plots,and the experiments of the relationships between density of a stand,forest benefit to conserve soil and water and soil water was conducted in the Caragana korshinskii Kom stand in Shanghuang Eco-experimental Station of the semi-arid region,Guyuan County,Ningxia Hui Autonomic Region of China. The results showed that the mean basal diameter of Caragana korshinskiiKom stand decreases with increasing density and there is a linear relationship between basal diameter and stand density,the stand coverage increases with increasing density and there is a logarithm relationship between coverage and density;the canopy interception increases with density and both of them is a power relationship;the surface runoff decreases with increasing density and the relationship between them is a logarithm functional relationship,the sediment charge in the runoff increases with reducing density and the relationship between them can be expressed by an "inverse-S shape"curve.Although the canopy closure increase with increasing density,and the effect of Caragana korshinskii Kom stand on soil and water conservation strenthens,but there is a limit in the course of vegetation rehabilitation because of the limit of soil water resources.When the cover degree is more than the limit,soil drying appears or was aggravated in the Caragana korshinskii Kom stand.