Abstract: High quality 5% Yb³⁺ doped Lu₂O₃ crystal was successfully grown by optical floating zone method. The growth parameters for the Yb:Lu₂O₃ single crystal by the optical floating method were explored and optimized. Its crystal structure was determined to be cubic structure, Ia space group by X-ray powder diffraction (XRPD) and the structure was analyzed. Chemical composition was determined by X-ray fluorescence (XRF) and the segregation coefficients of Yb³⁺ ion and Lu³⁺ ion was calculated to be 0.93 and 1.00, respectively.