Y₂O₃ transparent ceramics have broad applications including solid-state lasers, transparent windows, etc., owing to its excellent optical and physical-chemical properties. The dispersity of the powder among the fabrication process of transparent ceramics has attracted much attention from researchers for decades. In this paper, domestic commercial nanopowder was adopted as the starting material, and the dispersion of the powder was improved through mechanical force combined with HF acid-washing. Y₂O₃ transparent ceramics with high transmittance were achieved by slip casting and vacuum sintering. The results show that ultrasonic combined with HF acid-washing is an effective way to improve the dispersibility and sinterability of the powder, the D₅₀ of the powder reduces from 3.5 μm to 1.4 μm. The transmittance of the Y₂O₃ ceramic at 400 nm is improved from 65.5% to 71.5% for the sample after ultrasonic combined with HF acid-washing process. The results lay a solid foundation of preparation technology and theoretical basis for the application of Y₂O₃ transparent ceramics on solid-state lasers and transparent window materials.