Based on the design scheme of a main cable saddle for a mega bridge domestically, this paper employs the concrete plastic damage theory (CDP model) in conjunction with the finite element software ABAQUS for an optimized analysis of the structure of a new type of steel-concrete composite main cable saddle. Through a systematic analysis of the effects of different designs of the steel structure saddle head, different connection methods of shear keys, and the construction of the concrete saddle body on the load-bearing capacity of the composite saddle, the study shows that using a flat design for the bottom surface of the upper bearing plate on the saddle head leads to significant plastic tensile damage in the concrete saddle body. In contrast, designing the bottom surface of the upper bearing plate as curved significantly enhances the force performance of the steel-concrete composite main cable saddle. In the analysis and comparison of three types of shear keys: shaped steel, bolts, and PBL, it was found that the concrete saddle body on both sides of the shaped steel shear keys exhibited extensive plastic tensile damage; compared to shaped steel shear keys, the concrete damage on both sides of the PBL shear keys was more severe, and the concrete on both sides of the steel plate and the concrete tenon showed a wide range of plastic tensile damage, indicating that the bolt shear keys resulted in the least plastic tensile damage to the saddle body. To reduce the use of steel, controlling the thickness of the steel structure saddle head's upper bearing plate to 50mm is ideal, and the best control angle for the slope of the concrete saddle body on both sides of the saddle head is 45°, where the damage to the concrete saddle body is minimal. When the concrete material is switched from C50 to Ultra High Performance Concrete (UHPC), under the action of three times the design load, the plastic tensile damage at the center of the saddle body is significantly reduced to 0.2, markedly improving the ultimate load-bearing capacity of the steel-concrete composite main cable saddle. In summary, as a new type of construction, the steel-concrete composite main cable saddle has broad application prospects and significant value domestically. Through further research and practice, its extensive application in domestic bridge engineering can be promoted, offering more economical and efficient solutions for bridge construction, and enhancing the load-bearing capacity and safety performance of bridges.