YBO3:2 at.% Eu3+ was prepared by the solid state reaction and its temperature dependent luminescence was investigated for possible applications in temperature sensing. Phase composition of this material was confirmed by X-ray powder diffraction analysis and excitation and emission spectra were also provided. Under excitation of 355 nm, the fluorescence originating from5D0 and5D1 states varied as the temperature rose in a region from 333 to 773 K. The fluorescence intensity ratio (FIR) of5D0 and5D1 was investigated which increased significantly with the rise of temperature. The maximal relative sensitivity in the whole temperature range was 1.8% K–1 (at 333 K). The results recommended YBO3:Eu3+ as a new material of the FIR method for non-contact optical thermometry.