Hydrothermal or alcoholysis liquefaction are common pathways to produce biofuel in mild reaction conditions. However, the application was limited by the reliance of corrosive add and base catalysts and high-cost hydrogen donors. In this research, in-situ-prepared nano-Cu was employed for the first time as a methanol decomposition catalyst in a glycerol-methanol water solvent to generate hydrogen in situ for the hydrogenation-liquefaction of Miscanthus. Methanol was effectively decomposed to H-2, CO, and CO2 by the catalysis of Cu. The percentage of conversion of biomass into liquid product was over 90% at 350 degrees C for 4 h. Bio-oil with main components, including alcohols, esters, ethers, alkyl phenolics, and other glycerol-derived molecules, were obtained. This strategy also showed an excellent liquefaction capacity when other woody and herbaceous biomasses were selected as feedstock.