Up-conversion luminescent materials have been applied in non-contact optical temperature sensing technology due to their unique thermal sensitivity characteristics. Ca0.5Gd(WO4)2, with good thermal stability and optical properties, is suitable for the preparation of temperature-sensitive sensors. In this work, the Er3+/Yb3+ co-doped Ca0.5 Gd (WO4)2 phosphors were successfully prepared by high-temperature solid-phase method, and the influences of different Yb3+ doping concentrations on the phase structure, morphology and luminescence properties of the samples were studied. With the increase of Yb3+ doping concentration, the up-conversion and near-infrared luminescence intensity of Ca0.5 - Gd(WO4)2 : Er3+/Yb3+ sample first increased and then decreased, and achieved a maximum value when the Yb3+ doping concentration is 10 mol% . According to the relationship between pump power and luminescence intensity, it can be concluded that the up-conversion luminescence of Er3+ is a two-photon absorption process. In addition, the up-conversion luminescence of Ca0.5 Gd(WO4)2 : 0.5% Er3+/10% Yb3+ was measured in the temperature range of 313—573 K, and it was found that the relative sensitivity reached the maximum value of 0.0142 K-1 at 548 K. In conclusion, the Ca0.5 Gd(WO4)2 : Er3+/Yb3+ phosphor has potential application value in the field of optoelectronic materials, especially in non-contact optical temperature sensors. © 2022 Cailiao Daobaoshe/ Materials Review. All rights reserved.