<p>Weathering has a significant effect on the engineering properties of rocks, therefore the aim of this paper is to investigate the compressive properties, crack evolution trends and damage precursors of granite before and after weathering. For this purpose, uniaxial compression tests and Brazilian splitting tests were carried out with the help of acoustic emission, scanning electron microscopy and nuclear magnetic resonance equipment to complement the study. The results show that: after weathering, the porosity of the rock increases, the cementation between the mineral particles is weakened, and some minerals have been transformed into clay minerals; the fresh rock mainly exhibits axial cleavage damage, while the weathered rock mainly undergoes shear damage; the microscopic failures and internal damages of the rock during the damage process after weathering are reduced, and the degree of the damage is lowered; the signals of the tensile cracks with a high AF and the signals of the more shear The tensile crack signals with high AF values and more shear crack signals can be taken as the basis for determining the damage of the rock samples. The RA/AF values are used as the indicators of the damage of the rocks, and the dispersion of the RA/AF values in a certain time series is used to predict the damage of the rocks, and the use of the coefficient of variation to characterise the dispersion achieves a better effect. This study can provide a reference for understanding the changes in mechanical properties of granite before and after weathering and damage prediction.</p>