Ellipsometer　is　a　powerful　tool　to　determine　the　thickness　and　optical　properties　of　thin　films.　Usually,　traditional　spectroscopic　ellipsometer　employing　transmissive　lenses　for　beam　collimation　and　focusing　are　only　accurate　over　a　limited　spectral　range　due　to　high　chromatic　aberration　and　low　transmittance.　In　this　paper,　we　describe　a　ellipsometer　that　uses　all-reflective　focusing　optical　components　to　extend　the　wavelength　range　from　Deep-UV　200　nm　to　near-infrared　1000　nm　and　focuses　the　collimated　beam　into　a　small　spot　size　(36x49　mu　m).　This　focused　beam　spectroscopic　ellipsometer　includes　four　off-axis　parabolic　mirrors　and　two　flat　mirrors,　in　which　flat　mirrors　are　used　to　change　the　propagation　direction　and　compensate　the　polarization　changes　caused　by　off-axis　parabolic　mirrors　to　obliquely　focus　on　the　sample　surface.　By　careful　construction,　alignment,　and　calibration　of　the　rotating-compensator　ellipsometer,　we　measured　the　thickness　of　SiO2　thin　film　on　Si　substrate　with　a　maximum　absolute　error　of　2.15　angstrom　in　the　thickness　range　of　30　to　130　angstrom.