Abstract: Aiming at the problems of high processing cost and low efficiency in the processing of special-shaped parts, a machining method of special-shaped parts with fuzzy set optimization design was proposed. The main characteristic factors affecting the processing methods are analyzed, including part materials, structural features, machining accuracy requirements, form and position tolerance requirements etc. The optimization strategy for meeting the demand of precision, reducing cost and improving efficiency was presented. We adoped the membership function method of fuzzy set theory to fuzzify the influencing factors and alternative processing methods. Then the membership function was calculated by fuzzy set reasoning. Fuzzy decision-making optimizes the processing method by single factor and comprehensive factor decision-making method, which is used to optimize the design and machining of typical parts. Practice shows that the optimized scheme not only ensures the machining accuracy and surface quality of parts, but also improves the processing efficiency and reduces the production cost. The research results have reference value for similar special-shaped parts processing.