Abstract: As the core infrastructure of China’s Phase IV lunar exploration program, Queqiao-2 faces multiple challenges in the deep space environment, including radiation, extreme temperature fluctuations, and long-duration shadows. This article systematically expounds the design of its power supply and distribution system: For long-term stable loads and extended shadow conditions, a high-efficiency energy system composed of triple-junction gallium arsenide solar cells and lithium-ion battery packs was selected, providing 30.5 V bus voltage output based on a fully regulated bus architecture; through hierarchical protection and intelligent monitoring coordination, a highly reliable, self-healing multi-load distribution system was constructed; and a four-level series initiation pyrotechnic control strategy ensured reliable timing of critical operations. On-orbit data show that the solar cell array’s first-year current degradation rate is less than 3%, and the battery pack capacity retention rate exceeds 99%, verifying the system’s adaptability and reliability under extreme conditions and meeting the satellite’s full-cycle on-orbit usage requirements. The study can provide a reference for energy design in subsequent deep-space exploration missions.