This paper focuses on planetary scale excavation robots as a cutting-edge field of science and technology, and explores the key issues in their design and application. The article first systematically analyzes the extreme environmental conditions and unique needs of planetary excavation, and then highlights the central role of robots in planetary resource development. Based on these needs, the article proposes a series of performance indicators for excavation robots and discusses the overall mechanism design accordingly. The design covers a number of key components such as drilling, rotary drum, transfer mechanism and moving chassis, and the article also analyzes the specific function realization of these components in the planetary excavation process and the synergistic working mechanism among them. At present, the planetary scale excavation robot is still in the conceptual design stage, but its goal is to lay a solid technical foundation for the efficient development and utilization of planetary resources in the future.