Abstract: This study systematically investigates the deformation and instability mechanisms of surrounding rock in gob-side entry driving under hard roof conditions by adopting an integrated methodology of “theoretical analysis, numerical simulation, and coupled monitoring”. Based on the geological and mining conditions of the 21407 working face in a representative coal mine, a mechanical model and corresponding theoretical formulas for gob-side entry driving with a hard immediate roof under coupled static and dynamic loads were established. The analysis focuses on the influence of the cantilever beam structure in the goaf and the hard arc-triangle zone at the roadway end on surrounding rock deformation. An innovative three-dimensional monitoring system was developed, which incorporates 3D laser scanning for dynamic deformation capture and distributed bolt (cable) stress monitoring devices. This integrated “deformation-stress” monitoring system enables quantitative analysis of the full life-cycle deformation patterns of surrounding rock in hard immediate roof conditions. The results demonstrate that the surrounding rock of the gob-side entry is significantly affected not only by the static load from the cantilever beam in the goaf but also notably by dynamic pressure resulting from the suspended roof at the working face end. The deformation evolution exhibits five distinct stages: the excavation-affected period, stable creep period, long-term flow period, mining-affected period, and strong disturbance period. Through combined theoretical analysis and CDEM numerical simulation, the deformation and instability characteristics were identified as follows: floor heave shows a positive correlation with roof subsidence; the deformation of the small coal pillar side is greater than that of the solid coal side; and both sides demonstrate asymmetric and alternately evolving periodic deformation patterns. The superposition effect of static and dynamic loads in hard roof conditions forms a synergistic force source system. This research provides new perspectives and methodologies for theoretical innovation in understanding surrounding rock deformation in gob-side entries with hard immediate roofs, while also offering a more scientific basis for determining optimal support timing.