<p>The optimization of rubber powder utilization in asphalt remains hindered by the complex interactions between rubber powder and asphalt. To further investigate the influence of rubber powder distribution on the mechanical properties of rubber asphalt (RA), this study primarily focuses on the ductility of RA. Firstly, this study investigated the effect of rubber powder on the ductility of RA from a macro perspective. The results indicate that when the rubber powder content is between 20 and 25%, the low-temperature performance of RA is significantly improved. The mechanisms of fracture and agglomeration of RA have been investigated preliminarily using scanning electron microscopy, fluorescence microscopy, etc. Findings indicate that the ductility of RA is compromised due to rubber powder agglomeration, particularly when the rubber powder content is below 15% and above 25%. This is because rubber powder monomers and agglomerates profoundly impact the mechanical behavior of RA. Subsequently, Python programming and the Monte Carlo method were applied to develop the random distribution of rubber powder. By integrating this distribution model and based on the micro-observation, the processes of FDT were simulated, and the results indicated that the uneven distribution and irregular agglomeration of rubber powder led to a significant decrease in RA’s ductility. Specifically, when the rubber powder content is 25%, the rubber particles within RA can maintain a certain spatial distance while still being in a bonded state, which enhances its ability to resist external forces more effectively. This thorough investigation offers new mesoscopic insights into the complex interplay between rubber powder and asphalt performance, illuminating the various impacts of rubber powder monomers and agglomeration on the mechanical behavior of RA.</p>