One-dimensional La₂O₃:Eu³⁺ nanowires (NWs) and sub-micrometer samples (SMs) were fabricated by a hydrothermal method. Their photoluminescent characteristics were studied and compared. The results indicated that the exciton band in NWs blue-shifted in contrast to SMs. In comparison with the charge transfer (CT) band, the relative intensity of the exciton band in NWs was lower than that in SMs, which was attributed to the more energy transfer from the exciton band to surface defects. Frequency-selective-excitation spectra indicated that there existed three symmetry sites of Eu³⁺ ions in NWs and two sites in SMs. The results of the temperature dependence of ⁵D₁–⁷F₂ lifetimes indicated that the electronic radiative rate of ⁵D₁–∑⁷F_J in the two samples had hardly any variation and the nonradiative transition rate of ⁵D₁–⁵D₀ in NWs increased slightly.