The water resource is short,and rational utilization of water resource,especially soil water resource is imperative on the Loess Plateau.The canopy interception,runoff,soil water and plant growth was measured and soil water supply and soil water consumption was analysed in the perennial artificial Caragana shrub land in the Shangshong eco-experiment station of Loess Plateau.The results showed that canopies' interception increase with rainfall.The runoff relation of rainfall outside forest is linear.The first factor influencing soil water is precipitation,second is canopy interception.The relationship between rainfall and soil water supply is linear.The impact of rainfall on soil water was reduced with depth decrease.The largest depth of wetting by rainfall is 170 cm in 270 cm in 2004.Along with Caragana forest start to bud and fall into fast growth period,soil water consumption was increased gradually,and soil drying was intensitied in light drought year.The soil supply increase fast and soil water storage increased,but the soil water would be used by plant by the next year in rainy year.