Er3+:8YSZ nano-powders were prepared by chemical coprecipitation method with the Er3+ doping concentrations of 0.5~2.5mol%. The surface morphologies, phase composition, fluorescence spectra and up-conversion luminescence of the nano-powders were investigated. The results showed that the 8YSZ powders calcined at 800℃ for 2 h exhibited fine, uniform and near-spherical with the size of 40~60 nm. The phase compositon of the Er3+:8YSZ nano-powders prepared under all of the doping concentrations consisted of single cubic zirconia. With increasing the Er3+ doping concentrations, the light intensity of fluorescence spectra first increased, reaching the maximum value at 1.5 mol%, and then decreased. With increasing the calcination temperature, the light intensity of fluorescence spectra first increased, reaching the maximum value at 800℃, and then decreased. Both of green and red up-conversion luminescence intensity of the Er3+:8YSZ nano-powders reached the maximum values when the calcination temperature at 800℃. The green up-conversion luminescence intensity reached the maximum value at the Er3+ doping concentrations of 1mol%, while the red reached the maximum at 2.5mol%.