Abstract: The uplift deformation phenomenon occurring in the dam due to reservoir impounding appears rarely. To explore the influences of the hydro-geological structure of the rock mass on the uplift deformation, the mode of the hydro-geological structure inducing the generation of uplift deformation near the dam area is put forward through the researches on the existing literatures. The relative impermeable layer inclination to the downstream under the dam foundation and the relative permeable layer lying beneath the impermeable layer are the necessary hydro-geological conditions for the generation of uplift deformation. A numerical method based on the hydro-mechanical coupling theory is employed to study the influences of the variation of attitude elements on the spatial distribution law of uplift deformation occurring near the dam. It is shown that the shorter the distance between the exposure site and the dam, the greater the uplift deformation value. With the increase of the dip angle of the impermeable layer, the maximum uplift deformation near the dam increases firstly and then decreases. It is also indicated that the spatial distribution position of the uplift deformation is directly determined by the variation of dip direction.