Gd2O3:Ho3+,Yb3+ nanocrystals were synthesized via solvothermal method.X-ray diffraction(XRD),transmission electron microscopy(TEM),absorption and upconversion spectra were employed to characterize the synthesized nanocrystals.The results of XRD and TEM showed that obtained Gd2O3:Ho3+,Yb3+ nanocrystals were cubic in crystal structure and uniform spherical in morphology.The average crystallite size was calculated to be 7.5 nm.Green and red up-conversion emissions corresponding to(5F4,5S2)→5I8 and 5F5 → 5I8 transition were observed upon 980 nm excitation at room temperature.The results indicated that both green and red luminescence were based on the two-photon processes.Laser power and doping concentration dependence of the upconverted emissions were studied to understand the upconversion mechanisms.Excited state absorption and energy-transfer processes were discussed as the possible mechanisms for the visible emissions. Gd2O3: Ho3 +, Yb3 + nanocrystals were synthesized via solvothermal method. X-ray diffraction (XRD), transmission electron microscopy (TEM), absorption and upconversion spectra were employed to characterize the synthesized nanocrystals. The results of XRD and TEM showed that obtained Gd2O3: Ho3 +, Yb3 + nanocrystals were cubic in crystal structure and uniform spherical in morphology. The average crystallite size was calculated to be 7.5 nm. Green and red up-conversion emissions corresponding to (5F4,5S2) → 5I8 and 5F5 → 5I8 transition were observed upon 980 nm excitation at room temperature. The results indicated that both green and red luminescence were based on the two-photon processes. Laser power and doping concentration dependence of the upconverted emissions were studied to understand the upconversion mechanisms. Expedited state absorption and energy-transfer processes were discussed as the possible mechanisms for the visible emissions.