1T-TaS2, an archetypal quasi-2D compound, reveals strong electron-phonon (e-p) coupling responsible for charge-density-wave (CDW) instabilities leading to a series of phase transitions: from unmodulated structure into incommensurate CDW phase;then to nearly commensurate and finally to commensurate CDW state.Ta4+ ions adopt David star pattern,where 5d electrons on 12 of 13 ions form molecular orbitals leaving center ion with free S=1/2 spin.Despite huge interest in CDW phases,little is known about e-p coupling in TaS2.To our best knowledge no inelastic neutron experiment has yet been done on TaS2 which would otherwise reveal which particular phonon modes are involved at CDW transitions.We propose to investigate the temperature evolution of phonon density of states in 3 CDW phases by inelastic scattering using MARI with the aim of improving our understanding of e-p mechanism in CDW phases.