The space solar power station is a gigantic power satellite to provide the earth with continuous energy. The front-end system of space solar power station, solar concentrator, has significant influences on the optical performance. Regarding the proposed orb-shaped membrane energy gathering array scheme, this paper deals with the construction strategy of its large-scale spherical concentrator to reduce the complexity of manufacturing and improve the optical properties. The optical principle of the spherical concentrator is described and the spatial motion characteristic is presented. A novel construction strategy for the large-scale concentrator is proposed via partitioning octahedron on the sphere and polygonal partition. This paper evaluates the optical performance of the concentrator constructed by the novel strategy using ray tracing method. Performance parameters such as optical concentration ratio and collection efficiency are obtained. Comparison with the other strategies are also implemented. In addition, influence factors such as the sun's non-parallelism, the tracking precision, the orbital periodic motion, and the potential blockage effects of microwave transmitting antenna and supporting structure are mathematically discussed and evaluated. The numerical results indicate that the proposed strategy achieves a high collection rate, a small efficiency fluctuation, appropriate energy distribution, and relatively small splicing modules, which is conducive to improve optical performance and decrease difficulty in manufacturing.