The homogeneous precipitation method was used for preparing nanocrystalline erbium-doped Y2O3 with various molar concentrations. These materials synthesized in the system were characterized with XRD, SEM micrograph and PL spectra. Stokes and antiStokes PL emissions of Y2O3:Er3+ nanocrystals were investigated, whose intensities were varied evidently with a range of dopant erbium ions concentration. When the molarity of dopant erbium ions is close to 2.0%, the relative intensities of anti-Stokes PL spectra are dominant. From the XRD and SEM micrograph, the Y2O3:Er3+ nanocrystal with cubic structure is verified and the distribution of particles size is homogeneous. The experimental results indicate that the anti-Stokes emission results from twophoton absorption process in the Y2O3:Er3+ nanocrystal system.