The extraction and adsorption characteristics for three phenolic ketones with high physicochemical similarity among phenolic compounds, which are alcohol fermentation inhibitors in lignocellulosic biomass hydrolysates, were investigated. The most suitable basic extractant for selectively separating acetosyringone from three phenol ketones by reactive extraction was found to be trioctylphosphine oxide. In addition, it was found that adsorption using XAD16, a polymer neutral resin adsorbent, or physical extraction using hexane, was a suitable separation method for separation of 4'-hydroxyacetophenone (HAP) and acetovanillone (AVO). A five-step fractionation process including extraction and adsorption mentioned above has been first proposed to separate and concentrate the three phenol ketones present at equal mass percentages. When physical extraction with n-hexane and re-extraction with an aqueous NaOH solution were used as the steps 4 and 5 in the fractionation process respectively, it was possible to obtain almost 70% or more of the purity of three phenolic ketones.