Gd₂O₃:Yb3＋,Er3＋ nanophosphors were synthesized via a hydrot hermal synthesis method with the starting materials of Gd₂O₃,Yb₂O₃,Er₂O₃,HNO₃,CO(NH ₂)_2and C₁₂H₂₅SO₄Na. The samples were characterized by X-ray diffraction (XRD),differential scannin g calorimetry thermogravimetric analysis (DSC-TGA),fourier transform infrared spectrosc opy (FT-IR), transmission electron microscopy (TEM) and up-conversion luminescence (UCL) spectra.The results show that the molar ratio of Gd3＋ has a great influence o n the phase structure of the precursor.The precursor is composed of Gd₂(CO₃)₃·xH₂O when th e molar ratio of Gd3＋ is 4,which can be transformed into near-spherical Gd₂O_3powder with the average size of 30－40nm by calcini ng at 800℃ for 2h in air.Under 980nm infrared laser excitation,the strongest emission peak f or the Gd₂O₃:Yb,Er nanophosphors is located at 664nm,which corresponds to t he F9/2→I15/2 transition of Er ions.Moreover,the Gd₂O₃:Yb,Er nanophosphors also show green e mission peaks at 539nm and 562nm,which are attributed to the transitions of H11/2→I15/2 and S3/2→I15/2 of Er ions,respectively.The quen ching concentration of Er ions is 1%.The Gd₂O₃:Yb,Er nanophosphors show two-photo model emission mechanism at 800℃ .When the temperature increases to 1200℃,the emission mechanism chan ges into three-photo model.