Er∶Lu₂O₃ transparent ceramics are one of the candidate solid-state gain media for high efficiency and high power laser in the near and mid-infrared bands due to the advantages of high thermal conductivity, high thermal shock resistance, good spectral properties and low preparation temperature. Exploring the influence of Er³⁺ doping concentration (atomic number fraction) on the preparation and properties of Er∶Lu₂O₃ transparent ceramics for the related laser application is crucial for achieving high-quality Er∶Lu₂O₃ ceramics. In this paper, Er∶Lu₂O₃ transparent ceramics were fabricated using vacuum pre-sintering combined with hot isostatic pressing (HIP) post-treatment from the nano-powders synthesized by the coprecipitation method. The results show that the phases of all Er∶Lu₂O₃ nano-powders calcined at 1 100 ℃ with different Er³⁺ concentrations are almost consistent with that of the pure cubic Lu₂O₃ and the 10% Er∶Lu₂O₃ nano-powder shows better dispersibility. The average grain sizes of 0.3% and 10% Er∶Lu₂O₃ ceramics pre-sintered at 1 500 ℃ are 0.86 and 0.87 μm with the relative densities of 95.1% and 96.2%, respectively. The corresponding pre-sintered ceramics were HIP-ed at 1 750 ℃ show the in-line transmittance of 71.6% and 78.0% (thickness 2.9 mm) at 2 400 nm, respectively. Especially, the in-line transmittance of the 0.3% Er∶Lu₂O₃ ceramics sharply decreases in the short wave range due to the numerous remained residual pores. The absorption and emission spectra of 0.3% and 10% Er∶Lu₂O₃ transparent ceramics were calculated. 0.3% Er∶Lu₂O₃ ceramics possesses higher absorption and emission cross-sections around the band centered at 1.55 μm.