To　gain　more　insight　into　the　mechanism　of　the　separation　of　phenols　by　deep　eutectic　solvents　(DESs),　four　DESs:　tetraethylammonium　chloride　(TEAC)-ethylene　glycol　(EG),　TEAC-diethylene　glycol　(DEG),　TEACtriethylene　glycol　(TEG)　and　TEAC-tetraethylene　glycol　(TTEG)　were　prepared　for　the　extraction　of　phenols　from　model　oil.　Experimental　parameter　optimization　results　indicated　that　four　DESs　were　effective　in　extracting　phenols,　and　TEAC-EG　had　the　highest　extraction　efficiency　(EE),　with　EE　up　to　98.95%.　Subsequently,　the　formation　mechanism　of　DESs　and　the　extraction　mechanism　were　revealed　at　the　molecular/atomic　level　by　quantum　calculations　using　density　functional　theory　(DFT).　The　most　stable　configurations,　hydrogen　bonding　lengths,　and　interaction　energies　of　DESs　and　corresponding　systems　have　been　calculated,　and　the　weak　interactions　in　the　systems　were　visualized　and　further　analyzed.　The　results　showed　that　DESs　formation　were　mainly　due　to　a　combined　effect　of　hydrogen　bonding　and　van　der　Waals　(vdW)　forces.　Besides,　hydrogen　bonding　and　vdW　forces　between　DESs　and　phenol　were　the　main　forces　acting　to　extract　phenol,　and　the　hydrogen　bonding　within　DESs　was　weakened　when　DESs　interacted　with　phenol.