Abstract: The Institute of Modern Physics (IMP) of Chinese Academy of Sciences (CAS) was developing an intermediate energy heavy-ion microbeam endstation at Heavy Ion Research Facility of Lanzhou (HIRFL) which can make heavy-ion precisely targeted and exactly counted. The structurestatic analysis on vacuum window of different structures and materials was done with the aids of infinite element analysis software. The deformation and the equivalent stress of vacuum window were simulated. Then the safety of these candidates was investigated using the intensity theory. In addition, the small angle scattering and the transverse range of ions were simulated using SRIM code. The influence of the incident ions energy, the material and the thickness of the window, the air on the beam spot broadening were studied in detail. So the appropriate structure, material and thickness scale of vacuum window were put forward.