Monodispersed spherical Y2O3:Eu3+ nanocrystallines were successfully prepared by a novel gel-network coprecipitition process. The effect of reaction conditions on the resulting particles was investigated. XRD,TEM and fluoresce spectra were used to characterize the samples. The results show that the samples were spherical with a particle size of 13 nm-25 nm. Compared with micronscale Y2O3:Eu3+, a clear red shift occurs in the excitation spectrum of Y2O3:Eu3+ nanocrystalline prepared by the present work.