TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Conditions: The reaction conditions involve reaction temperature at 70-160 degrees C, reaction pressure under 0.1-10 MPa, and reaction with heating speed of 0.2-10 degrees C/minute. The hydrogen pressure of reaction is 0.1-10 MPa. The reaction system further comprises cosolvent when homogeneous catalyst is not dissolved in low molecular alcohol; and cosolvent can dissolve homogeneous catalyst and is mutually soluble with low molecular alcohol. Preferred Component: The homogeneous catalyst is metal complex, with metal having nickel, palladium, chromium, cobalt, molybdenum, ruthenium, copper or gold; ligand formed by using compound having carbonyl group, carbon to carbon double bond or triphenylphosphine as ligand, with metal; or (triphenylphosphine) palladium, nickel oleate, triphenylruthenium chloride, rhodium chloride or benzenetricarbonyl chromium. Preferred Contents: The mass ratio of homogeneous catalyst to bio-oil in reaction system is 1x 10-6-1x 10-2:1. The mass ratio of low molecular alcohol to bio-oil is 0.1-5:1. Preferred Methods: The method further comprises heating reaction system from room temperature to 60 degrees C at heating speed of 5 degrees C/minute, standing for 30-300 minutes, heating at 110 degrees C with heating speed of 8 degrees C/minute, and standing for 50 minutes; heating from room temperature to 70 degrees C at heating speed of 0.2 degrees C/minute, standing for 70 minutes, heating at 150 degrees C at heating speed as 2 degrees C/minute, and standing for 30 minutes; heating from room temperature to 110 degrees C at heating speed of 2 degrees C/minute, standing for 150 minutes, heating at 160 degrees C at heating speed of 10 degrees C/minute, standing for 30 minutes; heating from room temperature to 80 degrees C at heating speed of 2 degrees C/minute, standing for 50 minutes, and heating at 130 degrees C with heating speed of 8 degrees C/minute, and standing for 240 minutes; heating from room temperature to 80 degrees C at heating speed of 2 degrees C/minute, standing for 50 minutes, heating at 120 degrees C with heating speed of 8 degrees C/minute and standing for 240 minutes; or heating from room temperature to 80 degrees C at heating speed of 2 degrees C/minute, standing for 50 minutes, heating at 110 degrees C with heating speed of 8 degrees C/minute, and standing for 240 minutes. The method further comprises collecting gases in reaction system after cooling at 100-120 degrees C; and cooling and recycling low molecular alcohol and homogeneous catalyst.