Abstract: The extraction of coal resources under buildings not only improves resource utilization efficiency but also enables green coal mining. To ensure the stability of surface buildings affected by underlying coal extraction, this study analyzes the principle of mine solid waste bed-separation grouting filling technology, and then designs a surface bed-separation grouting scheme using theoretical analysis, followed by field application. The results show that: under fixed boundary conditions, grouting is directly applied to the main injection layer; under non-fixed boundary conditions, grouting is first applied to the secondary injection layer and then to the main injection layer. Using grouting parameters with a water-cement ratio of 1.3～1.5:1 and an injection pressure of 3～3.5 MPa can effectively reduce the periodic weighting step of the working face, increase the final support resistance, and exert a "pressing-down" effect. Meanwhile, the maximum surface subsidence, maximum subsidence velocity, and maximum curvature are all significantly reduced, demonstrating an "uplifting" effect. Surface bed-separation grouting technology thus enables the extraction of coal resources under buildings while protecting the surface buildings.