Abstract: The antenna array of large digital array radar generally adopts the form of frame design. Due to the large scale of the array, modular design is generally adopted in order to facilitate manufacturing, processing, transportation and erection. The frame form of a single module determines the stiffness of the array. Based on the multi-objective optimization method, this paper uses finite element analysis method to optimize the design of a typical antenna skeleton module. The rationality and effectiveness of the optimization design method are illustrated through the comparison and analysis of the optimization results.