Abstract: The low-rank coal in the Zhundong region of Xinjiang is characterized by abundant reserves but significant maceral heterogeneity. The distinct differences in microstructure and physicochemical properties between vitrinite and inertinite severely restrict the efficiency of coal separation and high-value utilization. To reveal the microstructural evolution laws of products enriched with different macerals, this study focuses on low-rank coal from the Nanlutian Open-pit Coal Mine in Xinjiang. Maceral-enriched samples with varying densities were obtained using the centrifugal float-sink method. Systematic characterization was conducted across four dimensions—microcrystalline structure, carbon skeleton morphology, surface functional groups, and chemical structure—using X-ray Diffraction (XRD), Solid-state ¹³C Nuclear Magnetic Resonance (¹³C-NMR), X-ray Photoelectron Spectroscopy (XPS), and Fourier Transform Infrared Spectroscopy (FTIR). The research results indicate that inertinite-rich samples exhibit highly ordered condensed aromatic structures with surface abundance of oxygen-containing functional groups such as C=O and COO—, demonstrating "rigid oxidized aromatic cluster" characteristics. Vitrinite-rich samples show loosely stacked aromatic layers with higher contents of aliphatic carbon and long-chain aliphatic structures, manifesting "flexible aliphatic network" characteristics. Intermediate density samples are not a simple linear superposition of the two; instead, they exhibit complex structural reorganization involving intensified aromatic cluster depolymerization and branching. This research characterizes the multi-scale structural differences in Zhundong low-rank coal macerals and elucidates the variance ranging from aliphatic side chains to oxidized aromatic skeletons. The findings provide a critical theoretical basis for optimizing fine separation processes and regulating pyrolysis/gasification parameters for low-rank coal.