(Tm0.01Y0.99)(2)O-3 transparent ceramics have been fabricated in a vacuum condition using high-purity Y2O3 and Tm2O3 powders as raw materials, and ZrO2 and tetraethyl orthosilicate (TEOS) as additives. Effects of ZrO2 and TEOS on controlling the growth of grain size were investigated to obtain high-optical-quality transparent ceramics. Self-compensation of ZrO2 at high temperature offers vacancies, which promote the diffusion and densification rate. Meanwhile, the solid solution formed by substitution and interstice mechanism improves the optical quality of transparent ceramics significantly. The growth of grain size under different criteria was observed by field-emission scanning electron microscopy. The spectroscopic properties were also investigated. The result indicates that ZrO2 is necessary for the sintering of yttrium-transparent ceramics, but TEOS fails to contribute in the yttrium system.