Abstract: To address the challenges associated with the safe extraction of coal resources beneath buildings, railways, and water bodies in the Pingdingshan mining area and the large-scale disposal and utilization of bulk coal gangue, a compound roof large mining height gangue–paste dense filling cooperative mining technology was proposed, and a full-height one-time paste filling technological system was developed. The system consists of a crushing, processing, and screening subsystem, a proportioning, mixing, and weighing subsystem, a pipeline pumping subsystem, and an automatic monitoring and control subsystem. In addition, key operational processes were established, including the reserved advanced passage technique, the staged sealing technique behind the support, and the gangue–paste dense filling cooperative filling process. Furthermore, a set of supporting equipment was developed, including an integrated excavation and bolting machine for advanced passage construction and a large mining height gangue–paste dense filling hydraulic support equipped with an inter-support suspended gangue-throwing belt conveyor. Based on these developments, the technological parameters of the large mining height gangue–paste dense filling cooperative filling process were optimized, and the rational filling ratio and filling step distance were determined. Field measurements were conducted to characterize the strata pressure behavior during large mining height gangue–paste dense filling cooperative mining, as well as the stress-induced compression and deformation characteristics of the filling body. On this basis, the feasibility of the large mining height gangue–paste dense filling cooperative mining technology was systematically explored, and a preliminary key technological framework for compound roof large mining height gangue–paste dense filling cooperative mining was established. Engineering practice conducted in the No. 11 Mine within the No. 2-1 (Ji group) coal seam demonstrates that the maximum convergence of the roadway sidewalls reached 38.8 mm, while the maximum convergence between the roof and floor was 40.7 mm. In addition, the maximum surface subsidence was measured as 84 mm, with a maximum surface inclination of 1.34 mm/m and a maximum curvature of 0.099 mm/m². These results indicate that the overburden strata control effect of the large mining height gangue–paste dense filling cooperative mining method is significant, thereby enabling the safe extraction of coal resources beneath protected areas while simultaneously achieving the efficient disposal and utilization of solid waste.