Nd3+/Yb3+/Tm3+ tri-doped CaTeO3 compounds were prepared by a solid-state reaction method.Bright blue up-conversion (UC) luminescence at around 476 nm,which corresponds to the Tm3+: 1G4 → 3H6 transition,was observed under 808-nm excitation.The Nd3+ → Yb3+ →Tm3+ energy transfer process was responsible for the strong blue up-conversion emission in the tri-doped phosphor.The Tm3+ blue up-conversion emission intensity was strongly dependent on the concentrations of Yb3+ and Nd3+.The possible up-conversion mechanisms for the Nd3+/Yb3+/Tm3+ tri-doped CaTeO3 phosphor are discussed,based on the Nd3+ and Yb3+ concentration-dependent UC spectra,near-infrared luminescence spectra and luminescence decay curves.