In　this　work,　the　technology　for　absorbing　methyl　tert-butyl　ether　(MTBE)　with　ionic　liquids　(ILs)　is　first　proposed　and　systematically　investigated　from　the　molecular　level　to　system　scale.　The　imidazolium-based　ILs,　[BzMIM]　[Tf2N]　and　[AMIM][Tf2N]　are　screened　from　272　IL　species　using　the　COSMO-RS　model.　The　absorption　mechanism　at　the　molecular　level　is　explored　by　combined　characterization　techniques　(i.e.　H-1　NMR　and　FT-IR)　with　quantum　chemical　(QC)　calculations　(i.e.　binding　energy　and　weak　interaction　analyses).　The　vapour-liquid　equilibrium　(VLE)　of　MTBE-IL　and　MTBE-triethylene　glycol　(TEG)　systems　are　experimentally　determined　and　predicted　through　the　UNIFAC-Lei　model.　The　results　show　that　the　model　can　well　quantitatively　predict　the　VLE　of　these　mixed　systems.　Moreover,　the　equilibrium　absorption　capacities　of　MTBE　in　ILs　and　TEG　are　measured　and　the　magnitude　is　in　the　order　of　[BzMIM][Tf2N]　＞　[AMIM][Tf2N]　＞　TEG.　The　equilibrium　stage　and　rate-based　models　on　the　basis　of　the　UNIFAC-Lei　model　is　established　to　perform　the　process　design　and　optimization　for　MTBE　absorption.　When　achieving　the　same　separation　task　(i.e.,　MTBE　content　in　the　product　gas　less　than　500　ppm　in　mole　fraction),　the　mixed　absorbent　of　[AMIM][Tf2N]　+　TEG　has　the　lower　loss　of　product　gas　and　the　lower　energy　demands　(i.e.,　heating　and　cooling　energy　along　with　exergy　demands)　compared　with　the　pure　TEG　and　pure　IL　processes.　This　validates　that　ILs　are　potential　absorbents　and　IL-based　mixed　absorbents　may　be　the　better　strategy　for　achieving　highly　efficient　absorption　of　MTBE.