The precise and efficient simulation of static and dynamic performance of lattice structure has emerged as a focal area of research. This paper proposes a simulation analysis method for the modification of additive manufacturing lattice structures with variable cross-section beams. Leveraging the dynamic response of 3D-printed lattice structures, we establish and solve an inverse problem model for the geometric parameters of variable cross-section beam elements. We conduct inverse problem calibration of variable cross-section beam parameters for lattice structures with different diameters and establish interpolation models for the geometric parameters of variable cross-section beams with varying diameters. Finally, we validate the effectiveness of the interpolation models for the geometric parameters of variable cross-section beams on lattice structures of different diameters and gradient lattice structures. The simulation analysis model of variable cross-section beams established in this study demonstrates comparable accuracy in dynamic performance simulation to solid element model, also significantly improves analysis efficiency. This study is expected to provide an efficient and accurate modeling foundation for the dynamic optimization design of complex gradient lattice structures.