In this work, Eu3+ doped CaWO4 phosphors with various concentrations were obtained by hydrothermal method. XRD and the FE-SEM were used to indicate the structure and morphology of the samples. The temperature-dependent excitation and emission spectra of Eu3+ doped CaWO4 phosphors were measured. Analyzing the test results found that the luminescence of WO42− decreased significantly with the increase of temperature, showing a normal thermal quenching trend, but the luminescence of Eu3+ showed a novel trend of first rising and then decreasing. This novel phenomenon is the result of enhancement of energy transfer effect from the matrix to Eu3+ with temperature increase. The thermal quenching trend of Eu3+ and WO42− luminescence is markedly different. So, the high relative sensitivity is obtained by using FIR of Eu3+ and WO42− to represent temperature. The maximum of relative sensitivity was 3.25% K−1 at 303 K. Meanwhile, the luminescence color of phosphor changed significantly from blue to orange-red with increasing temperature. To sum up, Eu3+ doped CaWO4 phosphor was a potential optical temperature sensing material.