Abstract: Series of cyclic drying-wetting tests have been performed under isotropic and deviator stress conditions using a medium-size triaxial test apparatus to study the deformation characteristics of rock-fill material under cyclic drying-wetting and the influence of stress state. The experimental results show that in the condition of isotropic stress, the wetting volumetric strain of rock-fill under low confining pressure increases with increasing confining pressure while its variation under high confining pressure does not follow this trend, and such wetting volumetric strain mainly occurs in initial wetting process. In the condition of deviator stress, wetting deformation takes a direction consistent with that of loading deformation at the initial wetting stage, while deformation during drying evidently turns its direction toward that of volumetric shrinkage, consistent with the characteristics of creep deformation. The wetting deformation at the initial stage dominates and the ratio of initial wetting axial strain over total wetting axial strain is about 75% ~ 95%. Under low confining pressure, initial wetting axial strain increases with an increase in confining pressure or stress level; under high confining pressure, its trend of variation with confining pressure is different. During cyclic drying-wetting, the deformation of rock-fill specimens (including volumetric and axial strains) increases gradually with time and tends toward a stable limit value. A hyperbolic model is recommended for description of the relationship of specimen deformation versus the number of cycles.