(NdxY0.9-xLa0.1)2O3 (x=0.005-0.04) transparent ceramics were fabricated by conventional solid-state processing. The radiative spectral properties of the ceramic samples were evaluated by fitting the Judd-Ofelt model with the absorption and emission data. (NdxY0.9-xLa0.1)2O3 ceramics have broad absorption and emission bands with a radiative decay time of 328 μs. The absorption cross section at 806 nm and stimulated emission cross section at 1078 nm are calculated to be 1.53 ×10-20 and 5.22 × 10-20 cm2, respectively. The product of quantum efficiency and the ionic concentration (ηN) exhibited a peak value at 1.5 at% Nd3+ ion concentration, while the lifetime decreases dramatically from 300 μs (0.5 at% Nd) to 49 μs (4.0 at% Nd). With 1.0 at% Nd:Y1.8La0.2O3 ceramics acting as a laser medium, continuous-wave output power of 1.03 W was obtained at 1079.5 nm under an absorbed pump power of 7.2 W, corresponding to a slope efficiency of 18.4%.