In order to analyze and optimize the design scheme of anchoring bolts for super-long cantilever steel supports, a calculation model for the cross-sectional stress of each anchoring bolt under variable parameter conditions was established. The continuous change process of the cross-sectional stress of all anchoring bolts of two kinds of super-long cantilever steel supports was simulated, and the influence mechanism of parameter changes on the cross-sectional stress of bolts was analyzed. Based on the principle of minimum stress of each bolt cross section, the design scheme of cantilever steel support is optimized and applied to practical engineering. The calculated stress of the bolts of each anchoring device was compared with the simulated stress of COMSOL, and the stress distribution cloud map was obtained. The numerical calculation results show that no matter the super-long cantilever steel support is fixed on the column or the beam, when the diagonal bracing beam is fixed at the 3/4 length position of the extended beam, the maximum normal stress combination and the average shear stress combination of all the anchorage bolt cross sections are the smallest. The average shear stress of the bolt cross section of the fixed section of the horizontal beam is the largest, and the maximum normal stress of the bolt cross section of the diagonal bracing beam is the largest. The research results can provide guidance for the design of super-long cantilever steel support and its anchorage device.