Monodispersed spherical Y2O3:Eu3+ nanocrystallines were successfully prepared by a novel gel-network coprecipitation process. The effect of reaction conditions on the resulting particles was investigated. XRD, TEM and fluorescence spectra were used to characterize the samples. The results show that the samples are 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 method.