This paper reports the structural, optical and luminescence properties of Yb3+/Er3+ codoped Y2O3 phosphor synthesized by combustion method. The prepared phosphor was characterized by X-ray diffraction (XRD). XRD studies confirm the body-centered cubic structure of the phosphor. The optical properties such as diffuse reflectance (DR), photoluminescence and thermoluminescence were studied. DR spectra were used to determine the bandgap of the phosphor. Mechanism of upconversion by two-photon and energy transfer processes are interpreted and explained. The color coordinates were measured and the color tunability was analyzed as a function of the 980 nm excitation source power. Different trapping parameters associated with the glow peak were calculated by various glow curve methods.