Abstract: Focusing on the technological characteristics of a large aerospace shell part, this paper establishes the basic positioning scheme, clamping device and clamp body for the workpiece. The required clamping force is calculated according to the cutting force generated during machining; on this basis, the driving cylinder is selected, a special T-shaped pressing plate is designed, and the overall scheme of the clamp body is finalized. To further investigate the influence of clamping force on the machining accuracy of the part, the finite element method is adopted to carry out static structural analysis and modal analysis on the workpiece, so as to guarantee the machining accuracy and structural reliability of the component.