The X-ray single crystal structure determination of Lu2O3 sesquioxide and of polycrystalline transparent ceramic fabricated by the unconventional spark plasma sintering (SPS) method is presented for the first time. High quality single crystals of Lu2O3 samples were obtained by using both the micropulling-down (渭-PD) method and the laser heated pedestal growth (LHPG) technique. The SPS method is promising for obtaining high-density ceramics with fine grains at a relatively low temperature within a short holding time. The structural characterizations helped to complete information about the cubic structure of Lu2O3 sesquioxide, not clear until now in the literature from only polycrystalline samples and has raised doubts among many researchers.