Abstract: Poor sealing effectiveness and low gas extraction efficiency in boreholes within deep, low-permeability coal seams remain among the most critical bottlenecks for the safe and efficient mining of coal resources. Glass microbeads, an industrial by-product of glass manufacturing, can reduce the density of cement-based materials while improving their mechanical properties due to their high strength and excellent stability. To investigate the effects of glass microbeads, flowability tests were conducted to assess the influence of glass microbead type and dosage. Subsequently, a series of mechanical and microstructural analyses, including uniaxial compression tests, creep tests, X-ray diffraction, and thermogravimetric analysis, were performed to evaluate the influence of hollow glass microbeads and silane coupling agents on the mechanical properties and energy evolution. The results showed that the incorporation of hollow glass microbeads enhanced the flowability of cement-based materials, with the optimal group achieving an 8% higher flowability than the reference group. Conversely, the incorporation of solid glass microbeads adversely affected flowability. The addition of hollow glass microbeads significantly improved the compressive performance of cement-based materials, where the optimal formulation attained a compressive strength of 55.025 MPa. Surface modification of hollow glass microbeads with the KH-550 yielded a further increase to 60.191 MPa. The synergistic use of hollow glass microbeads and isobutyltriethoxysilane significantly improved the long-term load-bearing and the high-pressure resistance of cement-based materials, enabling them to maintain strong compressive capacity under prolonged loading. The peak compressive stress of the optimal group reached 50.32 MPa, representing a 67.85% increase compared to conventional cement-based materials. The incorporation of these fillers significantly promoted the hydration degree of the cement-based material. This was evidenced in the optimal group by a lower content of Ca(OH)₂ and unhydrated C₃S, alongside an increased formation of C−S−H gel. This study elucidates the mechanisms by which silane coupling agents and hollow glass microbeads modify the properties of cement-based materials, providing a theoretical foundation for the development of advanced borehole sealing materials in coal mining applications.