Eu3+ and Bi3+ codoped ZrO2 nanocrystalline powders are prepared by chemical co-precipitation method. The room temperature characteristic emission of Eu3+ can be observed from each sample. We determine the crystal structures and luminescent properties of the samples. It is shown that the crystal phase of nanocrystalline ZrO2:Eu3+-Bi3+ powder calcined at 600 ℃ is tetragonal, and it turns into the mixture of tetragonal and monoclinic phase as temperature rises to 800, 950, and 1100 ℃. It is obvious that characteristic emission intensity of Eu3+ in the tetragonal phase is greater than in the mixed phase. Bi3+ can sensitize the room temperature characteristic emission of Eu3+ in nanocrystalline ZrO2.