Abstract: The Chang′e-6 lunar probe is designed to achieve the first robotic sampling and return mission from the far side of the Moon.Lunar far side is overall of rugged terrain and is lack of flat area for sampling on the surface.Two areas in Apollo basin within south pole Atiken basin （SPA）are selected as primary and backup targeted landing sites，the safety and reliability of landing，lift-off and surface operation process are ensured.In order to achieve new mission objectives based on fundamentally determined technical status，an optimal system design solution is put forward to reduce system changes.The risks associated with alterations of technical status are avoided.Through comparative analysis，a retrograde orbit around the Moon is determined，ensuring minimal system modifications and optimal system design.In consideration of the reduced and discontinuous duration of relay telemetry and control on the far side of the Moon for Chang′e-6，a phased，highly autonomous，and cooperative relay-assisted lunar surface operation timeline design is proposed to ensure the implementation during landing，lift-off and surface operation process.For payload carried by Chang′e-6，a system design is proposed by using data processing units as the central exchange hub to ensure electrical interface safety isolation；customized detection modes are also developed for different payloads to maximize detection benefits without affecting the completion of the main mission.These methods are applied in the Chang′e-6 mission，ensuring the success of the world′s first robotic sampling and return mission from the far side of the Moon，valuable reference and experience are provided for follow-up lunar exploration and deep space exploration missions.

Key words: Chang′e-6, lunar far side, mission analysis, retrograde orbit, hosted payload