Abstract: In response to the support challenge of non-uniform large deformation in relatively intact soft rock roadways under complex stress conditions, we take the gateway of the 203 working face in the No. 11 mining district of Yindonggou Coal Mine as the engineering background. Using a combined method of theoretical analysis and numerical simulation, the mechanism and optimization scheme of high-prestress anchoring support technology are systematically investigated. Based on suspension theory, composite beam theory, and reinforced arch theory, together with the Mohr-Coulomb strength criterion, a mechanical framework for support is established. Key parameters such as anchor cable length, row spacing, and spacing are derived according to the specific geological and mechanical conditions of the 11 m thick roof in the study area. Three roof thickness conditions — 4 m, 7 m, and 11 m — are simulated with FLAC^3D software to analyze surrounding rock stability and anchor cable response characteristics. The results show that 11 m is the critical self-stable thickness for this type of roadway, at which high-prestress anchor cables can form an effective load-bearing system, controlling surrounding rock deformation and the development of plastic zones. When the roof thickness is less than 7 m, anchor cables are prone to failure due to stress concentration or excessive plastic zones under the disturbance of the goaf, necessitating combined support. A gradient support scheme is proposed, which specifically addresses the stability control problems for different roof thicknesses and provides a theoretical basis and technical reference for the support of similar relatively intact soft rock roadways.