Roof water hazard represents a major safety threat in deep coal mining, closely associated with the propagation and connection of water-conducting fractures under coupled mining-induced stress and seepage effects. This issue is particularly prominent in the Jurassic coalfields of the Ordos Basin in western China, where the Cretaceous Luohe Formation sandstone aquifer serves as the primary water inrush source. Its strong heterogeneity and anisotropy significantly influence the development and severity of water hazards. Currently, the estimation of permeability parameters still largely relies on empirical assumptions, lacking scientific support from microstructural insights. This study focuses on the Luohe Formation sandstone from the Xinzhuang Coal Mine, employing low-field nuclear magnetic resonance (NMR) technology to systematically investigate the pore structure, permeability, and movable fluid occurrence characteristics across different mining depths (505–814 m), lithologies (fine, medium, and coarse sandstone), and orientations (horizontal/vertical). These experiments were complemented by pumping tests for comparative analysis. The results indicate that horizontal permeability is generally higher than vertical permeability, with the maximum anisotropy coefficient reaching 9.81 (fine sandstone). Sedimentary bedding is identified as the main factor controlling pore structure and seepage anisotropy. Movable fluids are primarily stored in medium and large pores, as well as fractures with T2> 10 ms. A significant orders-of-magnitude discrepancy exists between the permeability parameters derived from pumping tests and those from laboratory experiments, indicating that fractures dominate macroscopic seepage behavior. This supports the characterization of the aquifer as a typical “dual-porosity medium.” This research provides theoretical and data support at the microstructural level for the accurate prediction and prevention of roof water hazards.