The liquefaction of Salix psammophila, Caragana intermedia and Populus × Eu ramericana(Doda)Guineir cv. ’I- 214) in the presence of phenol under sulfuric catalysis was studied. The effects of reaction temperature, liquid ratio (phenol/wood ratio), reaction time and catalyst content on liquefaction were investigated. The results show: (1) Under the optimum conditions Salix. Caragana and Populus liquefaction can get reasonable results, and the liquefaction Populus is much easier than Sali.r and Caragana. (2) The reaction temperature has a greatest influence on liquefaction process, moreover, liquefaction process is affected by liquefaction ratio, reaction time and catalyst content at a certain extent. (3)The optimum condition of liquefaction for Populus is estimated as: temperature of 150℃ the reaction time of 120 rain, liquid ratio (phenol/wood ratio) of 3 and catalyst content of 7%. Under the processing parameters of temperature of 150 ℃ the reaction time of 120 rain, liquid ratio (phenol/wood ratio) of 4 and catalyst content of 7%, the residues rate of Salix and,Caragana were satisfied.