Eu3+ doped nanoLu3Al5O12 powders were prepared by ultrasonic atomization and coprecipitation method with Lu2O3, Eu2O3 and Al(NO3)3·9H2O as raw materials, and the obtained powders were sintered at various temperature. Xray diffraction and scanning electron microscopy were employed to characterize the particle size and phase composition of the nanopowder. The emission, excitation and phononside band spectra of Eu3+∶Lu3Al5O12 were measured. The result indicated when the sintering temperature was higher than 900℃, the luminous intensity was significantly enhanced and the optimum doping concentration of Eu3+ was 5~7 mol%. The Ω2 and Ω4 parameters of Eu3+ for optical transition were calculated from their emission spectra in terms of reduced matrix U(t) (λ=2,4,6) character for optical transitions. The results indicated that the intensity parameters Ω2 reached to minimum and electronphonon coupling to the maximum when the doping concentration of Eu3+ was ~5 mol%. With the increase of Eu3+ content, the optical parameter increased slightly and the electronphonon coupling became weaker. It suggests that the symmetry becomes weaker, the bands of Eu and O atoms become higher and the covalence of Eu and O atoms increases. The Ω2 of the powder shows an obvious lower value by comparing with those of Eu3+ in glass and crystal matrix, which is result from the symmetrical decreasing of the nanoparticles induced by a large number of defects and structural aberrations.