<p>The increase in the construction tasks of SPS (space solar power stations) has put forward an urgent demand for the efficient assembly of truss units. Currently, the method based on the cooperation of two or more robotic arms can flexibly complete the assembly tasks, but the costs of transportation and maintenance of the robotic arms are extremely high. Therefore, using a single robotic arm to achieve the efficient assembly of truss units has become a new development trend. However, due to the low functional integration and poor flexibility of current robotic arms, it is difficult for a single robotic arm to complete the above tasks. To solve this problem, this paper proposes a novel methodology for the design and selection of robot configurations for SPS truss unit assembly. Starting from the basic requirements of the assembly task for the robot, through the analysis and decomposition of walking, grabbing, and operating functions, the configuration design of each limb of the robot with pose or flipping requirements as constraints is gradually carried out. Then, 15 multifunctional robot configurations with the minimum number of joints that can achieve single-robot assembly are obtained. Moreover, three universal indexes are proposed to evaluate these robot configurations, namely the traversability of different functional limbs, compactness, and the number of joints. Based on this, the twelfth configuration is selected as the optimal result, and it is designated as the SPS-TuoA robot. Finally, kinematic analysis of the selected robot is performed to reinforce the rationale for the choice. The configuration design and selection work in this paper is the source of engineering applications and could provide theoretical and technical support for similar scenarios such as SPS truss unit assembly.</p>