Abstract: In order to improve the production quality and efficiency of large parts assembly and shorten the manufacturing cycle, the company has designed and manufactured a set of large parts attitude adjustment and alignment system. In the project, author designed and manufactured a CNC positioner for attitude adjustment and alignment, developed a set of algorithms for attitude adjustment and trajectory planning, and compiled a software system with process integration software as the core. The Siemens SIMOTION D455 motion controller is used as the execution unit of large components attitude adjustment system. The application shows that the system has good operability and reliability, greatly improves the assembly quality of large parts, reduces the labor intensity of personnel, and improves the labor productivity.