Weight is one of the critical factors limiting the performance enhancement of coaxial reverse transmission systems. Under identical operating conditions, a lighter coaxial reverse transmission system exhibits better performance. The torque-splitting transmission method, which employs one gear meshing simultaneously with multiple gears to distribute the load, is a commonly used design approach for achieving lightweight designs in coaxial reverse transmission systems. However, under the condition of lower power, the torque-splitting configuration may not significantly reduce weight. In fact, the transmission system might be lighter with a non-torque-splitting structure. To determine whether a torque-splitting design is suitable under given conditions, it is essential to explore the relationship between design power and minimum weight for both torque-splitting and non-torque-splitting structures. This study focuses on the configurations of coaxial reverse transmission system based on cylindrical gears, bevel gears, and face gears. The structural parameters of the transmission system components are treated as design variables, with strength and spatial dimensions as constraints, and weight as the objective. An optimization model for coaxial reverse transmission systems is constructed and solved using the NSGA-II algorithm to obtain the corresponding relationships between design power and minimum transmission weight for the three transmission configurations, both with and without torque-splitting structures. The results indicate that the cylindrical gear configuration is suitable for torque-splitting structures. The bevel gear configuration is suitable for non-torque-splitting structures at low design power and for torque-splitting structures at high design power. And the face gear configuration is more suitable for torque-splitting structures.