Abstract: Thin-walled parts are widely used in aerospace, electronic communication, automobile industry and other fields. Factors affecting parts machining deformation are clamping, cutting parameters, parts internal residual stress, can be selected by the appropriate cutting parameters and fixtures to reduce parts deformation. The fixture is one of the main factors affecting the deformation of thin-walled parts, but the design and manufacture lack of scientific theory guidance, which can not predict the performance. Aiming at a ring thin-wall part in the clamping due to the unreasonable clamping way caused the clamping deformation of the part is too large, a special fixture which can restrain the deformation of the part is developed. The binding force of the parts was calculated, and the influence of different clamping layout on the deformation of the parts was simulated by finite element software. The working principle and travel of special fixture are analyzed. The processing procedure was established and the actual processing was carried out. The research shows that the maximum deformation of parts is controlled within 0.05 mm by using special clamping layout, which is of great significance for improving the accuracy of parts.