Abstract: The seasonal and interspecific changes of drought resistance were studied in 6 species of trees in the Loess Plateau based on the data of main water parameters measured by using pressure-volume technique. The result showed that the drought resistance index (DI) value of the tested species was in a steady increase during the annual growing season except in the middle of annual rainy period, i. e. the second peak period of tree growth. During the period of serious water stress of soil profile, the DI values of 6 species had following order from big to small:Malus micromalus, Populus hopeiensis, Caragana korshinskii, Populus simonii, Populus beijingensis, Robinia pseudoacacia.

Key words: Tree species, Pressure-volume analysis, Water parameters, Drought resistance index