Structural analysis model of metro platform screen door (PSD) mechanical system was built, and FEA method was employed to study the modal and structural stiffness of PSD system for getting the natural frequencies and vibration modes from modal analysis, and obtaining the deformation and stress distribution of the whole PSD and its key parts. By the calculation model and method, the structural properties of the PSD system and its design feasibility were evaluated, which provided theoretical base for the optimum and reliability design of PSD system.