The　suitability　of　mixed　solvents　of　triethylene　glycol　(TEG)　and　ionic　liquids　(ILs)　as　gas　drying　agents　was　first　systematically　studied　from　the　phase　equilibrium　to　molecular　perspectives.　The　vapor　-liquid　equilibrium　(VLE)　for　mixed　systems　of　H2O　-TEG,　H2O　-[EMIM][Tf2N],　and　H2O　-TEG　-[EMIM][Tf2N]　were　experimentally　measured　and　predicted　using　the　UNIFAC-Lei　model.　The　results　showed　that　the　UNIFAC-Lei　model　can　be　successfully　extended　to　predict　VLE　from　binary　to　ternary　systems.　In　addition,　the　vapor　pressures　of　H2O　-TEG　are　lower　than　those　of　H2O　-[EMIM]　[Tf2N],　while　the　addition　of　TEG　into　H2O　-[EMIM][Tf2N]　can　significantly　reduce　vapor　pressure.　Molecular　dynamic　(MD)　simulations　demonstrate　the　relationship　between　the　VLE　behaviors　and　microscopic　mechanisms　of　H2O　-　TEG　-[EMIM][Tf2N]　and　further　validate　the　suitability　of　TEG　-[EMIM][Tf2N]　as　desiccants　due　to　hydrogen　bond　(HB)　interactions　presented　in　H2O　-TEG,　H2O　-[EMIM][Tf2N]　and　TEG　-[EMIM][Tf2N].　This　study　provides　theoretical　guidance　for　the　application　of　IL-based　mixed　absorbents　in　gas　drying　processes.(C)　2021　Elsevier　Ltd.　All　rights　reserved.