This paper presents a spectroscopic study of Er, Yb co-doped Y₂O₃ transparent ceramics with 20 at.% Yb₃₊ and varied Er₃₊ concentration (0.5 at.% to 5 at.%). Room-temperature absorption spectra and refractive indices were measured. Standard Judd-Ofelt analysis was applied and the intensity parameters were calculated. With Er₃₊ concentration increasing, Ω₂ decreases from 5.41 to 3.36, Ω₄ ranges from 0.96 to 1.29 and Ω₆ ranges from 0.64 to 0.72. The spectroscopic quality factor X_4/6 ranges from 1.46 to 1.88. The radiative lifetime of ₄I_13/2 manifold is longest in the Er, Yb co-doped Y₂O₃ transparent ceramic with 0.5 at.% Er₃₊ content. All suggest that the Er, Yb co-doped Y₂O₃ transparent ceramic could be a potential material for near-infrared laser application.