Methyl isobutyl ketone (MIBK) and diisopropyl ether (DIPE) are two commonly used extractants in industry, but their efficiency in extracting phenols, especially polyhydroxyphenols, is low. In the work, a highly-efficient extractant was proposed to extract phenolic compounds, including polyhydroxyphenols. The interactions between three extractants, cyclohexanone (CYC), MIBK and DIPE, and phenols were analyzed by the COSMO-RS method and CYC shows stronger interactions with phenols than MIBK and DIPE. The results of Fourier-transform infrared spectroscopy (FTIR) show that strong hydrogen bonds are formed between CYC and phenolic compounds, in agreement with the results of the COSMO-RS method. The effects of concentration, temperature and pH values on the extractant performance were studied. Results showed that the performance of CYC is the best, followed by MIBK and DIPE, whose performance is the worst. As CYC was used as the extractant, the distribution coefficients of the three phenolic compounds, phenol, resorcinol and phloroglucinol, are 96.7, 47.8, 13.0, respectively. These values are 35%, 263%, and 160% larger than those of phenol, resorcinol and phloroglucinol, respectively, corresponding to MIBK. CYC is a highly-efficient extractant for the extraction of phenolic compounds, including polyhydroxyphenol.