Abstract: The integrated three-degree-of-freedom macro-micro motion positioning platform is characterized by high positioning accuracy and low error. However, resonance between the platform and the support frame can severely affect its positioning accuracy. Focusing on the support frame, a key component, the natural frequency of the support frame was increased to enhance the platform’s positioning accuracy. Using SolidWorks and ANSYS Workbench, static analysis, modal analysis, and parametric optimization analysis were conducted in sequence.An optimization scheme was selected, and modal analysis was performed on the optimized model for validation. The natural frequencies before and after optimization were compared.The results showed that the first-order natural frequency of the support frame increased by 5.8%, effectively improving the platform’s positioning accuracy and achieving optimization of the platform’s performance.The research findings provide theoretical support for the optimization design of similar structures.