This study proposes a fractal damage calculation method to understand blasting damage laws at the macroscopic, mesoscopic, and microscopic scales of rock. The findings indicate that the binary graph derived from the Moments algorithm can represent minute cracks and exhibit less noise within the image, making it suitable for identifying and extracting macroscopic damage. A three-dimensional (3D) reconstruction technique provides visualization of macroscopic rock damage following an explosion. The extent of this damage is quantitatively assessed using the box dimension. Additionally, a multifractal method is introduced to comprehensively evaluate macroscopic and mesoscopic damage to rock post-blasting. The multifractal dimension calculations reveal that mesoscopic damage is a significant factor in overall blasting damage. The box dimension offers a straightforward, macroscopic evaluation method for assessing 3D macroscopic fractures, while the multifractal dimension more accurately evaluates macroscopic cracks and mesoscopic damage. Both methods emphasize different aspects and are equally effective for assessing blasting damage. The study focuses on blasting damage in rock, which occurs primarily in the crack zone. Rocks are inherently heterogeneous and anisotropic, making blasting damage mitigation challenging. Computed tomography (CT) provides a high-resolution, non-destructive imaging technique to assess macroscopic and mesoscopic damage. Fractal theory, introduced by Mandelbrot, has been widely applied to quantify self-similar objects. The fractal dimension measures the irregularity of complex shapes and reflects their space efficiency. Previous studies have applied fractal theory to evaluate rock damage, and recent studies have further enriched its applications in rock mechanics. The current study provides an accurate identification and quantitative evaluation of blasting damage at macro, meso, and micro scales based on fractal theory to clarify the multi-scale damage law of rock mass under explosive loads. The experiment uses sandstone specimens and employs lead azide as the explosive. The experimental conditions are designed to minimize energy loss and enhance stress wave transmission. The study aims to establish multi-scale blasting damage correlations and improve the understanding of blasting damage in rock.This study proposes a fractal damage calculation method to understand blasting damage laws at the macroscopic, mesoscopic, and microscopic scales of rock. The findings indicate that the binary graph derived from the Moments algorithm can represent minute cracks and exhibit less noise within the image, making it suitable for identifying and extracting macroscopic damage. A three-dimensional (3D) reconstruction technique provides visualization of macroscopic rock damage following an explosion. The extent of this damage is quantitatively assessed using the box dimension. Additionally, a multifractal method is introduced to comprehensively evaluate macroscopic and mesoscopic damage to rock post-blasting. The multifractal dimension calculations reveal that mesoscopic damage is a significant factor in overall blasting damage. The box dimension offers a straightforward, macroscopic evaluation method for assessing 3D macroscopic fractures, while the multifractal dimension more accurately evaluates macroscopic cracks and mesoscopic damage. Both methods emphasize different aspects and are equally effective for assessing blasting damage. The study focuses on blasting damage in rock, which occurs primarily in the crack zone. Rocks are inherently heterogeneous and anisotropic, making blasting damage mitigation challenging. Computed tomography (CT) provides a high-resolution, non-destructive imaging technique to assess macroscopic and mesoscopic damage. Fractal theory, introduced by Mandelbrot, has been widely applied to quantify self-similar objects. The fractal dimension measures the irregularity of complex shapes and reflects their space efficiency. Previous studies have applied fractal theory to evaluate rock damage, and recent studies have further enriched its applications in rock mechanics. The current study provides an accurate identification and quantitative evaluation of blasting damage at macro, meso, and micro scales based on fractal theory to clarify the multi-scale damage law of rock mass under explosive loads. The experiment uses sandstone specimens and employs lead azide as the explosive. The experimental conditions are designed to minimize energy loss and enhance stress wave transmission. The study aims to establish multi-scale blasting damage correlations and improve the understanding of blasting damage in rock.