Abstract: As a crucial approach for achieving efficient CO₂ capture in coal-fired power plants, oxy-fuel combustion technology for pulverized coal has emerged as a major focus of global research due to its substantial potential to reduce CO₂ emissions. In light of China's reliance on coal as a primary energy source, a comprehensive understanding of the complex reaction networks and microscopic interaction mechanisms of pulverized coal under oxy-fuel combustion conditions is essential for advancing the sustainable utilization of coal. However, traditional experimental methods, constrained by the disconnection between macroscopic statistical properties and microscopic reaction details, has struggled to precisely reveal the influence mechanisms of various factors on coal pyrolysis/combustion processes or the dynamic molecular-level evolution during reactions. With recent advancements in computational chemistry, cross-scale simulation methods integrating Reactive Molecular Dynamics (ReaxFF MD) and Density Functional Theory (DFT) have provided a new paradigm to overcome these technical barriers. Building on this foundation, this study initiates from three-dimensional grid-based coal structural models and extends to coal-matrix analog models. Through molecular and quantum chemical cross-scale investigations, it systematically examines product release patterns, nitrogen migration characteristics, and key reaction mechanisms during pulverized coal pyrolysis and combustion. The work specifically analyzes the regulatory mechanisms of oxy-fuel combustion atmospheres (CO₂/H₂O) on these processes, while probing the functional mechanisms of characteristic coal components (characteristic electron groups and metal atoms) under oxygen-enriched conditions. Finally, several critical issues has been summarized and discussed in this study, including the revelation of the reaction processes within the intricate coal structure, the development of reaction force fields, and the refinement of molecular models. This endeavor aims to lay a solid theoretical foundation for the development of novel oxygen-rich combustion technologies.