Double perovskite compounds have attracted wide attention due to the advantages of low phonon energy, easy doping with rare earth ions, and stable physicochemical properties. To obtain novel temperature-sensitive upconversion materials, a series of up-conversion luminescent materials K3InF6:Er3+,Yb3+ with double perovskite structure were synthesized by hightemperature solid-phase method in this paper. In addition, the composition, structure and luminescence properties were systematically characterized by Xray powder diffractometer (XRD), field emission scanning electron microscope (FE-SEM) and fluorescence spectrometer (PL), respectively. The results show that the prepared up-conversion luminescent materials are all double perovskite structure, and the samples emit bright green light under 980 nm laser excitation, and the up-conversion luminescence intensity of the samples is maximized when the ratio of amounts of Er3+ and Yb3+ are 0.05 and 0.25, respectively. Meanwhile, the up-conversion luminescence mechanism involved in the samples is discussed in detail by measuring the up-conversion luminescence spectra of variable power. The temperature sensing performance of the samples in the range of 303 to 573 K was also investigated based on the fluorescence intensity ratio (FIR) technique, and a maximum absolute sensitivity of 9.5×10-3 K-1 was obtained when the temperature was 483 K. All the results indicate that K3InF6:Er3+,Yb3+ up-conversion luminescent material has high sensitivity and has a promising application in the field of temperature sensing.