The spectral line of HeI 1083nm is important and potential to measure the magnetic field of the solar upper chromosphere. In this paper, we present a newly developed Stokes polarimeter for measuring the polarized signals at this wavelength. In this device, two Liquid Crystal Variable Retarders (LCVRs) were employed as electro-optical modulators and a Wollaston prism as analyzer and polarized beam splitter. Compared to the commonly used linear-polarized analyzer, the Wollaston prism analyzer has main advantage to minimize the seeing-induced contamination of earth's atmosphere, as it produces simultaneous images by the two perpendicular polarization states. A novel optical design which focuses the two beams on different detector areas is described. And the accurate calibration methods are introduced too.