1-Butyl-3-methyl imidazolium hexafluorophosphate ([Bmim]PF6) and tributyl phosphate (TBP) were combined as a binary extractant to extract phenol. Influencing variables on the enrichment performance of the binary extractant such as the volumes of [Bmim]PF6 and TBP, pH, temperature and salt were investigated. The enrichment mechanism was explored. The results showed that a high enrichment factor of 128 was achieved in 30 mL TBP-30 mL [Bmim]PF6 system at a low temperature of 273.15 K without addition of salt and buffer solution. The high enrichment performance was attributed to the interaction between P==O of TBP and ?H of phenol OH.