The underground rock body is often affected by external factors, after repeated cycles of loading and unloading, it will lead to the increase of internal cracks in rock and the change of local stress environment. Therefore, the triaxial graded cyclic loading and unloading tests with different upper limit stresses were carried out on sandstone, and the damage mechanical properties and the laws of energy evolution of sandstone were obtained. The test results show that under the conditions of graded cyclic loading and unloading, the stress-strain curve of sandstone is characterized by hysteresis loops and downward bending, and the hysteresis loops are gradually enlarged with the increase of stress. Under the cyclic loading and unloading with different upper limit stresses, as the number of cycles increasing, the axial elastic strain and axial plastic strain of sandstone show linear relationships with the number of cycles, while the sudden drop of axial plastic strain indicates that the internal pore cracks of sandstone are compacted rapidly. Meanwhile, the input energy and elastic energy curves are very similar during the cycling process, showing an upward trend of nearly exponential curve. Dissipation energy grows relatively slowly in the initial cycling stage, which indicates that the original cracks in the sandstone are compressed and closed; while in the mid-cycling stage, the dissipation energy shows a nearly linear growth trend, which indicates that the rock samples are in the stage of stable expansion of the cracks. The dissipation energy ratio shows a sudden decrease in the initial cycling stage; while in the mid-cycling stage, it maintains an approximate horizontal trend. In addition, under the graded cyclic loading and unloading, there is a linear relationship between the degree of damage to sandstone and the number of cycles, indicating that the number of load cycles has a significant impact on the degree of damage to sandstone.