| This paper studys soil moisture distribution and composition of soil water energy at unsaturated zone in East Gansu. The results are as follows:Soil water mass content characteristics are logarithmic in the more arid Potou wasteland，sand and non-cultivated soil in the Loess Plateau of East Gansu, while moisture content of the arable soil is affected by its, soil texture, displaying quite difference. In the unsaturated zone of the Loess Plateau, the proportion of solute potential is about 15% at Potou wasteland, while it can be up to about 25% in the farmland. Matric potential accounts for nearly 80% in Potou of the arable and is 60% in average content in famland, which is of the laryest proportion of the soil water perten-tial. HCO3- plays a leading role of anios in the solute potential of the unsaturated zone，and leading cation is Ca2+ in the loess area. Soil solute potential in the weight of the plasma ions is the laryest HCO3- and Ca2+， which is about 50% and 25% respectively of the solute potential in the Loess Plateau, Na+ and Cl- are about 10%. |