This experiment researched the static and dynamic characteristics and made an optimization design of cover edge mechanism for square tin cover glue-injection and drying machine. The 3D model of cover edge mechanism was created by Ansys Workbench, and the method of finite element analysis was used for the static analysis and modal analysis of up plate structure. The optimization mathematic model was created and the analytical results before and after optimization were compared. Through the analysis, the stress and deformation before and after optimization and the modal vibration mode were obtained. The up plate thickness after optimization decreased by 30%, and the width reduced by 27%, while the equivalent stress deformation increased, the natural frequency reduced, and the quality decreased by about 7.1 Kg. The analysis showed the optimization of up plate structure was reasonable, and the quality was reduced and the cost was saved in the condition of ensuring the strength and rigidity.