Temperature is one of the fundamental parameters for thermodynamics and its accurate detection is nec-essary.The novel strategy of luminescent materials based on the fluorescence intensity ratio technique has been promised for thermometers in more practical environments to overcome the drawbacks of con-ventional thermometers in recent.Herein,the novel single-phase K3Gd(VO4)2 ∶Tb3+/Sm3+ phosphors were successfully prepared,and the 4G5/2 → 6H9/2 (Sm3+) and 5D4 → 7F5 (Tb3+) transitions could be promised for luminescent thermometers.Besides,under the double-excited states of charge transfer band (CTB,317 nm) and 4f-4f (478 nm) excitations,the K3Gd(VO4)2∶Th3+/Sm3+ phosphors exhibited different con-centration quenching mechanisms in energy transfer processes and also showed superior absolute sensing sensitivity (Sa) and relative sensing sensitivity (Sr).Especially,the maximum Sa and Sr values reached up to 0.568 K-1 and 11.24％ K-1,respectively and the temperature resolution of the KGV:0.2Tb3+/0.01Sm3+phosphor was higher than 0.004 K under the excitation wavelength of CTB (317 nm),indicating that the double-excited states in the single-phase KGV:Tb3+/Sm3+ phosphors with superior sensing sensitivity could be a novel candidate for potential optical thermometers.