Abstract: In this paper, a special pneumatic multifunctional fixture for milling machine is designed and manufactured according to the structure and processing characteristics of the processed parts. In order to ensure the fixture has good strength, ANSYS Workbench software was used to analyze the forces in the plane milling and drilling process of the fixture workpiece system. The results show that the maximum stress produced by the assembly under the action of drilling force and cutting force is far less than the yield strength of the material, and the maximum displacement produced is within the range of machining error. After the sample trial-manufacture and field test, the products produced with special fixture meet the precision requirements of workpiece size and geometric tolerance and reach the expected goal. Therefore, the fixture structure design is reasonable, which has certain promotion application value.