The major objective of this study was to characterize the root system of the 1～3 year old seedlings of Caragana microphylla,an important shrub species in Longxi hilly region of the Loess Plateau,China.Root morphology,growth and development,distribution and nodule characteristics were determined after excavation.The results show that the growth rate of the major root of Caragana microphylla was much greater than that of the stem.The ratio of root to shoot ranged from four to six.The lateral roots were found mainly on the 5～15 cm section of the major root.The radicles of Caragana microphylla in average elongated 5 cm upward,implying a reasonable sowing depth of 3 cm.The nodules concentrated mainly on the major root and the first-division lateral roots in the 10—30 cm soil layer.The fast-growing,well-developed root system and nodules provided the plant with superior drought resistance and ecological functions of improving soil quality and conserving soil and water.Compared with spring sowing,fall sowing agreed to local light,heat,and water resources better and should be promoted to a higher level.