The potassium dihydrogen phosphate (KDP) crystal elements served as switcher and frequency converter are the key components in large laser system for inertial confinement fusion (ICF). Such kinds of crystal components, which can be treated as thin plates, are usually fixed on a vacuum chucker connected to the worktable and fabricated by the single point diamond turning machine. The bend due to the vacuum chucking is one of the most important contributors aggravating the distortion of the crystal plate. In this paper, we analyze the influence of vacuum chucking on the distortion of the crystal plate by using finite element analysis method. The calculating results show that the parameters of the chucker, such as the size of the chucking hole, the distribution of the holes, the vacuum pressure and the status of holding the crystal plate, are closely related to the distortion. Another interesting result is that the chucking force from the holes would have effect on the waviness of the surface.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.