Abstract: Based on the technological characteristics of a certain large-scale aerospace shell part, the basic positioning scheme, clamping device and fixture body of the part were determined. The clamping force was determined by the cutting force during processing, and the corresponding cylinder was selected. A special hook-shaped pressure plate was designed to determine the fixture body. To further analyze the influence of clamping force and clamping area on the processing accuracy of the part, the finite element method was used to conduct static and modal analysis of the workpiece, further ensuring its accuracy and reliability.