Thermal stabilizing effect of Yb 3+, Er 3+codoping into TiO2 powder prepared by sol-gel method and its upconversion characteristics were analyzed. The effect of TiO2 : Yb 3+, Er 3+ions on crystallinity and phase transition was studied by X-ray diffraction (XRD). The change of band-gap energy induced from Yb and Er codoping was analyzed by UV-Vis. The band-gap energy of TiO2 have been slightly narrowed by Yb 3+, Er 3+codoping, which indicated that the Yb 3+,Er 3+ions can enhance the photo-catalytic property of TiO2. green and red up-conversions of Yb 3+and Er 3+co-doped Y2O3 :Yb 3+, Er 3+phosphor were analyzed by PL equipped with 980 nm laser.