Abstract: Actual stress path of the unsaturated loess caused by the damage of irrigating induced can be approximated as normal stress and deviatoric stress remains unchanged, while the process of gradually reducing of matrix suction. In order to research the strain characteristics of unsaturated loess under wetting conditions, the Q₃ Loess in the Southern Tableland of Jingyang County has been taken as the research object, and the experimental research on hygroscopic properties of unsaturated loess under the control of different hygroscopic properties of the matrix suction(initial water content) has been carried out from the angle of the unsaturated soil. The results show that, the deformation and failure are happened in the soil samples under a steady primary stress with the decrease of the matrix suction, but no damage shear surface occursin the whole deformation process; the further research suggests that soil samples have strong water sensitivity from the plastic limit water content to liquid limit water content.When the water content increases to the plastic limit water content, the strain is developed rapidly, which reveals the strong collapsiblecharacteristics of Q₃ loess and the causes of shallow landslide and avalanche. Finally, for the same soil, the change curves of its matric suction and strain are similar,their differences in the curve may be caused by the differences of soil and the errorbetween the instruments that made by human factors.