Method for extracting phenolic compounds from biological oil

The invention discloses a method for extracting phenolic compounds from a biological oil, and relates to an extraction process of the biological oil. The method comprises the steps of preprocessing the biological oil, and extracting a distillate containing phenolic compounds; adding a soluble salt into the extracted distillate containing phenolic compounds to obtain a solution A; adjusting a pH value of the solution A to be more than 7 so as to obtain a solution B; placing the solution B in a water bath and heating to obtain a complexing precipitate; collecting the complexing precipitate, and performing vacuum filtration to prepare a filter cake; placing the filter cake into hydrochloric acid to perform replacement, extracting with an extractant, and performing vacuum drying on the extract liquor to extract the phenolic compounds. By use of a soluble metal salt as a precipitant and an acetic acid ester or dichloromethane solution as the extractant, the phenolic compounds can be extracted from a biomass pyrolysis oil. Compared with the prior art, the method disclosed by the invention is simple in process, and the purities of the extracted phenolic compounds can be up to more than 96%.