In this study, stable isotope compositions of the precipitation and soil water of five different kinds of land use patterns in Wang Mao ditch small watershed on the Loess Plateau were analyzed, the aim was to understand the characteristics of stable isotopes along the soil profile, and provide a scientific basis for understanding the mechanisms of soil water movement, the identification of model parameters and the ecological protection and reconstruction. The results showed that: (1) The variation ranges of δD (or δ18O) in the precipitation was from -118.08‰ (or -16.13‰) to -14.37‰ (or 1.41‰), with a mean value of -37.36‰ (or -5.65‰). The variation range of δD (or δ18O) in soil water of five kinds of land use was from -92.36‰ (or -12.48‰) to -34.98‰ (or -5.01‰), with a mean value of -60.18‰ (or -7.81‰). (2) There were significant differences in the changes of hydrogen and oxygen isotope. Soil permeability of the five kinds of land use was as follows: grassland > terraced fields > forest land > dam land > slope cropland. Soil water evaporation fractionation in different land use patterns was as follows: terraced fields > grassland > dam land > slope cropland > forest land. (3) The woodland and grassland “preferential flow” phenomenon was obvious; the grassland “preferential flow” was the maximal, and the woodland could extend the “preferential flow” path obviously. (4) Hydrogen and oxygen isotopic values in the 160, 200 and >200 cm soil layers of the grassland, woodland, and terrace were relatively stable. The dam land and sloping farmland might affect the quality and recharge of groundwater significantly.