Abstract: Due to limitations of current physical testing equipment, it is difficult to track the internal contact characteristics and motion information of specimens. To investigate the influence of confining pressure unloading rate on the meso-scale damage and fracture behavior of sandstone, the unloading rate was set as the sole variable. Numerical simulations under constant axial loading and unloading confining pressure conditions were conducted. During the unloading process, meso-scale parameters such as the local structure of force chains, inter-particle contact forces, coordination number, and contact orientation were extracted. The geometric structure and statistical mechanical characteristics of the specimens under two unloading rates were computed and compared. The results show that the continuous adjustment and redistribution of inter-particle contact forces are closely related to the unloading rate, resulting in differences in macroscopic mechanical responses. Under different unloading rates, particle contact and arrangement patterns exhibit differentiated adaptive bearing characteristics. The contact force distribution tends to become more dispersed during unloading, leading to enhanced heterogeneity in particle loading, increased local stress concentration, and a higher degree of force chain disorder. Under rapid unloading, insufficient particle rearrangement leads to a sharp decrease in the effective coordination number, with particle motion dominated by global adjustments. In contrast, under slow unloading, particles are able to adjust more adequately, forming complex local arrangement patterns. Tensile failure is the dominant fracture mode under both conditions; however, differences are observed in crack distribution, connectivity, and local fracture characteristics. Under rapid unloading, high-stress zones inside the specimen are underdeveloped, resulting in scattered crack patterns without a clear concentration trend. Under slow unloading, stress redistribution is more complete, leading to more pronounced local stress concentrations and the formation of through-going fracture surfaces. The meso-scale contact information reflects the macroscopic characteristics of the specimens. The findings provide theoretical guidance for the design of physical test schemes under confining pressure unloading conditions and the analysis of meso-scale rock fracture mechanisms.