Abstract: Understanding the evolution of meso-structure and mechanical properties of fractured granite under wetting-drying and freezing-thawing cycles is of considerable significance for slope stability assessment,safe operation of mining engineering,and analysis of long-term service performance. To quantitatively investigate the influence of these cyclic actions on the meso-structure of fractured granite,CT scanning and Low-field Nuclear Magnetic Resonance(LF-NMR) techniques were employed to systematically characterise the fracture evolution,pore structure parameters,and pore size distribution of granite specimens subjected to various cycle numbers. In addition,cyclic loading-unloading tests were conducted to examine the macroscopic mechanical response. The results indicate that with increasing numbers of wetting-drying and freezing-thawing cycles,both the number and size of micro-cracks within the granite continuously increase,and the fractures gradually evolve from a discrete distribution into an interconnected network,accompanied by a marked enhancement in pore connectivity. The pore structure progressively shifts from being dominated by micropores towards mesopores and macropores;specifically,the proportion of micropores decreases by 12. 36%,while the proportions of mesopores and macropores increase by 5. 54% and 6. 82%,respectively. The macroscopic mechanical test results show that the stress-strain response of granite under cyclic action exhibits distinct staged characteristics. After 30 cycles,the peak strength decreases by 8. 6% relative to the initial peak strength,displaying a consistently deteriorating trend that is closely correlated with the evolution of pore structure. The wetting-drying and freezingthawing cycles,through repeated water absorption,freezing and thawing,induce pore expansion and fracture coalescence,which constitute the primary intrinsic mechanism responsible for the degradation of mechanical performance in fractured granite.