Taking the flange structure of a three-phase asynchronous motor (frame number 280) as the object, solid modeling is carried out by using SolidWorks three-dimensional software. The strength of the structure is analyzed and checked by using material mechanics theory and finite element analysis software. The design of this type of flange structure is optimized. The analysis support for the strength check of this type of motor flange structure is provided. The finite element solution to the strength analysis of motor flange structure is operational and effective.