Abstract: Aiming at the dual requirements of structural performance and lightweight design for modern high-performance airborne systems, a collaborative optimization model of the assembly connection system considering both the assembly connection position and the material distribution of connected components is proposed in this paper. The model adopts distributed beam-shell elements for the finite element characterization of the assembly connection system, in which the positions of connection reference points and the material pseudo-densities of components are defined as geometric design variables and topological design variables, respectively. On this basis, the sensitivity formulas of the optimization objectives and relevant constraints with respect to the two types of design variables are derived. The globally convergent method of moving asymptotes (GCMMA) is applied to solve the optimization problem, realizing the lightweight design of the airborne assembly connection system under static loading. Numerical simulation results show that compared with the traditional fixed connection position design method that neglects connection characteristics, the proposed collaborative optimization method can significantly improve the static stiffness and structural comprehensive performance of the assembly connection system. This research provides a new method and insight for the optimal design of assembly connection structures of aerospace equipment.