Abstract: The study mainly introduces five kinds of bio-oil refining methods—hydrogenation, catalytic pyrolysis, emulsion, catalytic esterification and molecular distillation. Bio-oil refining technologies have their respective problems. For example, catalytic pyrolysis has advantages of simple equipment and low cost but catalyst is easily coked and deactivation; emulsion has simple operation but high cost and more energy consumption; catalytic esterification is a good modification methods but the quality of oil is not high after modification. All these bio-oil refining technologies are hard to realize industrialization. Finally, a new method of bio-oil refining in the CO/H2O systems was also introduced.