Abstract: Mobile robot processing technology provides a new technical means for the manufacture of large spacecraft capsule. Compared with the traditional manufacturing process based on CNC machine tools, there is a lack of a systematic framework and method for machining process planning. For this reason, taking the processing of large spacecraft capsule as an example, a process architecture of mobile robot system processing is proposed. Based on the overall process flow of large spacecraft capsule manufacturing, the task flow for mobile robots is combed, and the robot processing process elements are comprehensively summarized and optimized according to the requirements of tool distribution at the production site. At the same time, facing the practical needs of precision control and task allocation in mobile robot processing, three typical problems in process planning process, including hierarchical precision control, station planning and processing space partition splicing, are introduced in detail and specific solutions are given. Finally, taking a capsule as the processing object, the case verification of processing planning for mobile robot is completed. The results show that it can provide technical guidance for high-precision and high-efficiency machining of large spacecraft cabin using mobile robots.