The　life　cycle　environmental　sustainability　of　the　natural　gas　(NG)　dehydration　process　using　novel　dehydrant　[EMIM][Tf2N]　ionic　liquid　(IL)　has　been　evaluated　using　a　＂cradle　to　grave＂　life　cycle　assessment　(LCA)　methodology,　and　the　results　were　compared　with　the　traditional　dehydrant　triethylene　glycol　(TEG).　The　LCA　results　of　[EMIM][Tf2N]　production　indicate　that　the　precursors＇　production　stage　is　the　main　hotspot　that　contributes　to　most　of　the　environmental　burdens.　Meanwhile,　compared　with　cation　production,　the　anion　production　has　higher　environmental　impacts　(about　69.8%　on　average)　in　most　of　the　categories　except　human　toxicity　potential　(HTP)　and　freshwater　aquatic　ecotoxicity　potential　(FAETP).　The　comparative　LCA　results　show　that　the　NG　dehydration　with　[EMIM]　[Tf2N]　has　significantly　higher　environmental　impacts　than　TEG　in　all　categories,　but　the　TEG-based　scenario　shows　worse　impacts　than　the　[EMIM]　[Tf2N]　in　the　use　stage　(about　4.5　times　higher).　Moreover,　the　sensitivity　analysis　proved　that　the　dehydrant　recovery　ratio　is　a　crucial　parameter.　When　considering　the　dehydrant　recovery,　the　environmental　impacts　are　comparable　for　[EMIM]　[Tf2N]　and　TEG-based　NG　dehydration　processes.　This　study　can　give　guidance　on　novel　material　synthesis　and　process　improvement　from　the　life　cycle　perspective,　and　encourage　further　research　on　the　potential　of　employing　novel　IL　as　traditional　NG　dehydrant　alternatives.