Abstract: Acetic acid, phenol, guaiacol and 4-methylguaiacol in bio-oil aqueous fraction were extracted and separated experimentally with the choice of hydrophobic ionic liquid BmimNTf₂ as extractant. The effects of extraction time and extractant dosage on the extraction efficiency were explored. With the help of density functional theory (DFT) calculations, the interaction mechanism between BmimNTf₂ and phenol was also clarified. The results showed that under the optimal extraction condition (m_IL/m_W = 0.4, extraction time = 5 min), the extraction efficiencies of acetic acid, phenol, guaiacol and 4-methylguaiacol in the aqueous fraction were 2.71%, 95.41%, 92.04%, and 97.98%, respectively. It was indicated that BmimNTf₂ had better selectivity and superior extraction efficiency for phenols in bio-oil aqueous fraction. The results of DFT calculation demonstrated that the strong hydrogen bonding interaction as well as weak vdW interaction between BmimNTf₂ and phenols played an important role in extraction and dephenolization of bio-oil aqueous fraction. The phenols in BmimNTf₂ can be effectively removed by alkali washing treatment to achieve recovery of BmimNTf₂ and next high efficiency extraction.