Understanding how grain packing and pore distribution affect fracture evolution in rocks remains a key challenge in rock mechanics, with significant implications for applications such as mining, reservoir management, and geotechnical engineering [1]. Accurate prediction of rock behavior under stress is essential for enhancing safety and operational efficiency in these fields. The Discrete Element Method (DEM) has emerged as a powerful tool for simulating rock mechanics by representing rock as an assembly of discrete particles, allowing the study of micro-scale interactions that drive macro-scale fracture patterns [2]. This approach excels in linking microstructural properties to overall mechanical behavior [3]. In this study, DEM was employed to investigate the effects of varying grain packing densities and pore distributions on rock fracture evolution. Our simulations reveal that higher grain packing density enhances rock strength, while lower packing density or increased porosity results in reduced strength. Additionally, pore distribution influences fracture patterns: uniformly distributed small pores lead to diffuse cracking, whereas larger, heterogeneous pores promote localized fracture zones. Grain size distribution further modulates fracture complexity, with uniform grain sizes resulting in simpler deformation patterns and broader distributions generating more complex crack networks. These findings underscore the critical role of microstructural heterogeneity in rock failure. By quantifying the impacts of pore and grain distributions, this study contributes to a refined predictive framework for fracture evolution in rocks, offering insights applicable to real-world geomechanical challenges.