Abstract:【Objective】To master the deformation characteristics and the law of energy dissipation of Jiangxi red clay under the condition of shear loading-unloading.【Methods】The direct shear loading-unloading tests are finished, and the strength and deformation properties and the law of energy dissipation are studied.【Results】The mechanical behavior of red clay under various normal stresses, including shear stress, shear displacement, normal displacement and energy dissipation, are obtained.【Conclusion】The dissipation energy increase rate under shear loading and unloading is comparatively lower for low normal stress as compared to high normal stress. On the whole, the dissipation of energy has positive correlation with the normal stress, and the greater the normal stress, the greater the energy consumed by the plastic deformation. The dissipated energy under the same unloading conditions increases with the increasing of numbers of unloading the red clay exhibits shear shrinkage during unloading and loading in a direct shear test. Normal displacement increases during the unloading stage, followed by an increase and then decrease during reloading, resulting in shear expansion deformation. Shear expansion ends when the shear displacement reaches its value before unloading. Shear unloading will increase the normal displacement and the shear shrinkage of red clay, and this effect of unloading on the normal displacement becomes weaker with the increase of normal stress.