Due to the complex structure, poor rigidity and high accuracy requirements of thin-walled parts, the assembly of thin-walled parts is mainly completed manually. There are problems such as low degree of automation, low product yield, poor efficiency and heavy reliance on the technical level of workers. In order to improve product quality and production efficiency, automatic assembly equipment is urgently needed. The assembly unit of thin-walled parts needs to be classified and matched according to the online measurement data. The traditional industrial robot takes up a large working space. The parallel robot has a flexible structure and takes up a small space. In this paper, a design scheme of thin-walled parts automatic sorting assembly unit is designed to replace the traditional manual sorting and assembly production mode. Firstly, according to the functional requirements of thin-walled parts classified assembly, the parallel structure is designed, and the dynamic model and kinematic model of the parallel structure are established. The change law of velocity and acceleration of parallel structure during rapid movement is analyzed. The angle data curve of three active arms and intermediate branch chain changes smoothly without sudden change. The angular velocity and angular acceleration are relatively stable, which ensures the working accuracy of the measuring camera. The stability of parallel mechanism meets the design requirements. The displacement curve of the moving platform coincides with the predetermined trajectory, and the results show that the designed mechanism can meet the functional requirements. The structure has small working space, can realize the automation of thin-walled parts assembly, and ensure the quality of products.