Abstract: Drawing on China’s experience in the application of conductors and the construction of towers for large crossings, a JLHA1/G6A-500/280 high-strength steel-reinforced aluminum-alloy conductor and a 455 m-high crossing tower were selected as the calculation conditions. In accordance with the current load code, an exact catenary model was adopted, with the aluminum-section stress constraint considered and the wind-pressure height coefficient iteratively determined from the mean conductor height of each span. Under the conditions of flat-terrain meteorological zone 3010 and a navigational clearance of 60 m, the theoretical maximum span was approximately 2,873 m. The results show that the maximum span approaches its peak when the anchor-span length is 1,400–1,500 m. As the anchor-span length increases from 300 m to 600 m, the maximum span increases rapidly from approximately 2,443 m to 2,763 m, after which the increase gradually diminishes. Where route conditions are constrained, an anchor-span length of approximately 700 m is recommended. At this anchor-span length, increasing the anchor-tower conductor attachment height beyond 150 m has a negligible effect on the maximum span. The results provide a reference for span-capability analysis, route layout, and the selection of transmission schemes for long-distance river crossings.