Raman scattering measurements of K2Sr(MoO4)2 were performed in the temperature range of 25-750 ℃.The Raman spectrum of the low-temperature phase α-K2Sr(MoO4)2 that was obtained by first-principle calculations indicated that the Raman bands in the wavenumber region of 250-500 cm-1 are related to MoO bending vibrations in MoO4 tetrahedra,while the Raman bands in the wavenumber region of 650-950 cm-1 are attributed to stretching vibrations of Mo-O bonds.The temperature-dependent Raman spectra reveal that K2Sr(MoO4)2 exhibits two sets of modifications in the Raman spectra at ～ 150 ℃ and ～ 475 ℃,attributed to structural phase transitions.The large change of the Raman spectra in the temperature range of 150 ℃ to 475 ℃ suggests structural instability of the medium-temperature phase β-K2Sr(MoO4)2.