The purpose of this paper is to analyze the body structure of the autocycle frame because the population density is high in Taiwan. Therefore, the safety and the durability of the scooter-body structure are especially important. SolidWorks cartography software, Solid modal, combines with the finite element software ANSYS Workbench, is used to advance the static and the modal analysis in this paper. In order to validate the finite element method, the finite element modal is adjusted until its parameters match the experimental ones by comparing the modal analysis date by the finite element method and experiment respectively. In addition, many fixing bases with different geometric type of the shock absorbers are designed to research the change of the natural frequencies by changing the density and thickness of the tubes.