Bio-oil,produced from the fast pyrolysis of biomass,contains a wide variety of functional groups and molecular weights including acids,aldehydes,ketones,sugars,phenols,and lignin-derived oligomers,etc.Thus,bio-oil has been considered as one of the important renewable chemical intermediates and fuel resources.However,as the high-value compounds in bio-oil were generally at low concentrations,the application of bio-oil was difficult and limited so far.Fractionation is an effective method to extend the application ways of bio-oil based on the corresponding properties and components of the different fractions.In the present study,the compounds isolation of bio-oil was performed using solvent extraction method as well as water precipitation method.The enrichment of various fractions,such as PL(pyrolytic lignin),phenol monomers,sugars,aldehydes,ketones and carboxylic acids,was achieved by their polarity and solubility in different solvents.