Abstract: In order to upgrade bio-oil through hydrofining under the operating conditions of atmospheric pressure, low temperature and catalyst-free, the technology of non-thermal plasma discharge unit for gas-liquid two-phase were applied. The influence law of operating voltage, gas flow rate, reaction time and other factors on the hydrodeoxygenation and physicochemical properties of bio-oil were investigated systematically by the self-designed non-thermal plasma discharge device for gas-liquid two-phase. The results showed that with the increase of operating voltage and gas flow rate, the deoxygenation rate and the high calorific value of gas-liquid two-phase discharge hydrofining biological oil first increased and then decreased. With the extension of reaction time, they first increased and then stabilized. Compared with the catalytic pyrolysis and fast pyrolysis bio-oil, the content of alcohols, phenols and ketones in gas-liquid two phase discharge hydrogenation of refined bio-oil were relatively low, and hydrocarbons increased significantly. Refined bio-oil quality was also improved, which confirmed that the feasibility of gas-liquid two phase discharge hydrofining biological oil technical scheme.