Abstract: The micro-fracturing process of marble samples under uniaxial compression, taken from the surrounding rock of the Jinping II cascade hydropower station, was recorded by using meso-mechanical testing schemes based on the scanning electron microscopy (SEM). Fracture spacing of these samples is analysed herein by statistical theory and compared with macro-fracturing process, and the probability distribution of micro-fracture spacing is generalized by an extreme-value distribution of damage parameters. Appling the basic principle of energy dissipation, we developed a damage model of macro- and meso-fracture information in the framework of irreversible thermodynamics and applied it to simulation of stress-strain relationships. The results show that all the calculated stress-strain curves fall within the range between two experimentally measured envelope curves. The damage parameter D that contains macro- and meso-fracture information is more sensitive to damage condition than the ones and containing macro-fracture information only. And the growth of these parameters presents prominent staged features.