NOVELTY - Liquefaction of solid residue using a lignocellulosic feedstock after enzymatic saccharification and ethanol fermentation involves: taking the lignocellulosic feedstock after enzymatic saccharification and ethanol fermentation to detects solid residue lignin content; and liquefaction occurs in the pressure container in the solid residue and the organic solvent under the action of a catalyst, where the organic solvent is ethanol, propanol, anhydrous or anhydrous alcohol, and the catalyst is aluminum chloride, aluminum sulfate and zinc sulfate.    USE - For liquefaction method solid residue using a lignocellulosic feedstock after enzymatic saccharification and ethanol fermentation (claimed); as biomass fuel ethanol fermentation residues and biomass feedstocks rich in lignin liquefaction.    ADVANTAGE - The method uses catalyst specifically selected to effectively lower the liquidus temperature, where the solid residue of the fermentation increases the rate of liquefaction and degradation degree residues can be generated more and low molecular weight liquid product. The method can be applied as biomass fuel ethanol fermentation residues and biomass feedstocks rich in lignin liquefaction, with low liquefaction temperature, with easily available raw materials. The method is simple with high efficiency.    DETAILED DESCRIPTION - Liquefaction of solid residue using a lignocellulosic feedstock after enzymatic saccharification and ethanol fermentation: taking the lignocellulosic feedstock after enzymatic saccharification and ethanol fermentation to detects solid residue lignin content; adding per gram of solid residue selected from the lignin content of 65-90 wt.% in a pressure vessel and then adding an organic solvent and a catalyst, and drying the residue in oven with oven-dry weight ratio of the solid volume of the organic solvent is calculated as l:1:4-1:30 kg, and adding oven dry catalyst in an amount of 2-20 wt.% of the solid residue, where the organic solvent is anhydrous ethanol, anhydrous alcohol or anhydrous alcohol and the catalyst is aluminum chloride, aluminum sulfate and zinc sulfate; liquefying the solid residue in the liquefaction step at 200-300 degrees C for 1-4 hours in the pressure vessel.